diff --git a/lib/types/thread-permission-types.js b/lib/types/thread-permission-types.js
--- a/lib/types/thread-permission-types.js
+++ b/lib/types/thread-permission-types.js
@@ -124,10 +124,7 @@
   userSurfacedPermission: userSurfacedPermissions.EDIT_CALENDAR,
 };
 const editEntries = threadPermissions.EDIT_ENTRIES;
-const descendantEditEntries =
-  threadPermissionPropagationPrefixes.DESCENDANT +
-  threadPermissions.EDIT_ENTRIES;
-const editCalendarPermissions = new Set([editEntries, descendantEditEntries]);
+const editCalendarPermissions = new Set([editEntries]);
 
 const knowOfSecretChannelsPermission = {
   title: 'Know of secret channels',
@@ -170,42 +167,16 @@
   userSurfacedPermission: userSurfacedPermissions.CREATE_AND_EDIT_CHANNELS,
 };
 const editThreadName = threadPermissions.EDIT_THREAD_NAME;
-const descendantEditThreadName =
-  threadPermissionPropagationPrefixes.DESCENDANT +
-  threadPermissions.EDIT_THREAD_NAME;
 const editThreadDescription = threadPermissions.EDIT_THREAD_DESCRIPTION;
-const descendantEditThreadDescription =
-  threadPermissionPropagationPrefixes.DESCENDANT +
-  threadPermissions.EDIT_THREAD_DESCRIPTION;
 const editThreadColor = threadPermissions.EDIT_THREAD_COLOR;
-const descendantEditThreadColor =
-  threadPermissionPropagationPrefixes.DESCENDANT +
-  threadPermissions.EDIT_THREAD_COLOR;
 const createSubchannels = threadPermissions.CREATE_SUBCHANNELS;
-const descendantCreateSubchannels =
-  threadPermissionPropagationPrefixes.DESCENDANT +
-  threadPermissionFilterPrefixes.TOP_LEVEL +
-  threadPermissions.CREATE_SUBCHANNELS;
 const editThreadAvatar = threadPermissions.EDIT_THREAD_AVATAR;
-const descendantEditThreadAvatar =
-  threadPermissionPropagationPrefixes.DESCENDANT +
-  threadPermissions.EDIT_THREAD_AVATAR;
-const descendantTopLevelCreateSidebars =
-  threadPermissionPropagationPrefixes.DESCENDANT +
-  threadPermissionFilterPrefixes.TOP_LEVEL +
-  threadPermissions.CREATE_SIDEBARS;
 const createAndEditChannelsPermissions = new Set([
   editThreadName,
-  descendantEditThreadName,
   editThreadDescription,
-  descendantEditThreadDescription,
   editThreadColor,
-  descendantEditThreadColor,
   createSubchannels,
-  descendantCreateSubchannels,
   editThreadAvatar,
-  descendantEditThreadAvatar,
-  descendantTopLevelCreateSidebars,
 ]);
 
 const deleteChannelsPermission = {
@@ -214,13 +185,7 @@
   userSurfacedPermission: userSurfacedPermissions.DELETE_CHANNELS,
 };
 const deleteThread = threadPermissions.DELETE_THREAD;
-const descendantDeleteThread =
-  threadPermissionPropagationPrefixes.DESCENDANT +
-  threadPermissions.DELETE_THREAD;
-const deleteChannelsPermissions = new Set([
-  deleteThread,
-  descendantDeleteThread,
-]);
+const deleteChannelsPermissions = new Set([deleteThread]);
 
 const addMembersPermission = {
   title: 'Add members',
@@ -228,18 +193,11 @@
   userSurfacedPermission: userSurfacedPermissions.ADD_MEMBERS,
 };
 const addMembers = threadPermissions.ADD_MEMBERS;
-const descendantAddMembers =
-  threadPermissionPropagationPrefixes.DESCENDANT +
-  threadPermissions.ADD_MEMBERS;
 const childOpenAddMembers =
   threadPermissionPropagationPrefixes.CHILD +
   threadPermissionFilterPrefixes.OPEN +
   threadPermissions.ADD_MEMBERS;
-const addMembersPermissions = new Set([
-  addMembers,
-  descendantAddMembers,
-  childOpenAddMembers,
-]);
+const addMembersPermissions = new Set([addMembers, childOpenAddMembers]);
 
 const removeMembersPermission = {
   title: 'Remove members',
@@ -247,13 +205,7 @@
   userSurfacedPermission: userSurfacedPermissions.REMOVE_MEMBERS,
 };
 const removeMembers = threadPermissions.REMOVE_MEMBERS;
-const descendantRemoveMembers =
-  threadPermissionPropagationPrefixes.DESCENDANT +
-  threadPermissions.REMOVE_MEMBERS;
-const removeMembersPermissions = new Set([
-  removeMembers,
-  descendantRemoveMembers,
-]);
+const removeMembersPermissions = new Set([removeMembers]);
 
 const changeRolePermission = {
   title: 'Change roles',
@@ -261,10 +213,7 @@
   userSurfacedPermission: userSurfacedPermissions.CHANGE_ROLES,
 };
 const changeRole = threadPermissions.CHANGE_ROLE;
-const descendantChangeRole =
-  threadPermissionPropagationPrefixes.DESCENDANT +
-  threadPermissions.CHANGE_ROLE;
-const changeRolePermissions = new Set([changeRole, descendantChangeRole]);
+const changeRolePermissions = new Set([changeRole]);
 
 const editVisibilityPermission = {
   title: 'Edit visibility',
@@ -272,13 +221,7 @@
   userSurfacedPermission: userSurfacedPermissions.EDIT_VISIBILITY,
 };
 const editPermissions = threadPermissions.EDIT_PERMISSIONS;
-const descendantEditPermissions =
-  threadPermissionPropagationPrefixes.DESCENDANT +
-  threadPermissions.EDIT_PERMISSIONS;
-const editVisibilityPermissions = new Set([
-  editPermissions,
-  descendantEditPermissions,
-]);
+const editVisibilityPermissions = new Set([editPermissions]);
 
 const managePinsPermission = {
   title: 'Manage pins',
@@ -286,10 +229,7 @@
   userSurfacedPermission: userSurfacedPermissions.MANAGE_PINS,
 };
 const managePins = threadPermissions.MANAGE_PINS;
-const descendantManagePins =
-  threadPermissionPropagationPrefixes.DESCENDANT +
-  threadPermissions.MANAGE_PINS;
-const managePinsPermissions = new Set([managePins, descendantManagePins]);
+const managePinsPermissions = new Set([managePins]);
 
 const reactToMessagePermission = {
   title: 'React to messages',
@@ -297,13 +237,7 @@
   userSurfacedPermission: userSurfacedPermissions.REACT_TO_MESSAGES,
 };
 const reactToMessage = threadPermissions.REACT_TO_MESSAGE;
-const descendantReactToMessage =
-  threadPermissionPropagationPrefixes.DESCENDANT +
-  threadPermissions.REACT_TO_MESSAGE;
-const reactToMessagePermissions = new Set([
-  reactToMessage,
-  descendantReactToMessage,
-]);
+const reactToMessagePermissions = new Set([reactToMessage]);
 
 const editMessagePermission = {
   title: 'Edit messages',
@@ -311,10 +245,7 @@
   userSurfacedPermission: userSurfacedPermissions.EDIT_MESSAGES,
 };
 const editMessage = threadPermissions.EDIT_MESSAGE;
-const descendantEditMessage =
-  threadPermissionPropagationPrefixes.DESCENDANT +
-  threadPermissions.EDIT_MESSAGE;
-const editMessagePermissions = new Set([editMessage, descendantEditMessage]);
+const editMessagePermissions = new Set([editMessage]);
 
 const manageInviteLinksPermission = {
   title: 'Manage invite links',
@@ -322,13 +253,7 @@
   userSurfacedPermission: userSurfacedPermissions.MANAGE_INVITE_LINKS,
 };
 const manageInviteLinks = threadPermissions.MANAGE_INVITE_LINKS;
-const descendantManageInviteLinks =
-  threadPermissionPropagationPrefixes.DESCENDANT +
-  threadPermissions.MANAGE_INVITE_LINKS;
-const manageInviteLinksPermissions = new Set([
-  manageInviteLinks,
-  descendantManageInviteLinks,
-]);
+const manageInviteLinksPermissions = new Set([manageInviteLinks]);
 
 export type UserSurfacedPermissionOption = {
   +title: string,
@@ -388,8 +313,7 @@
     threadPermissionFilterPrefixes.OPEN +
     threadPermissions.VISIBLE,
 
-  // join_thread | child_open_join_thread | descendant_opentoplevel_join_thread
-  threadPermissions.JOIN_THREAD,
+  // child_open_join_thread | descendant_opentoplevel_join_thread
   threadPermissionPropagationPrefixes.CHILD +
     threadPermissionFilterPrefixes.OPEN +
     threadPermissions.JOIN_THREAD,
diff --git a/lib/types/thread-permission-types.test.js b/lib/types/thread-permission-types.test.js
--- a/lib/types/thread-permission-types.test.js
+++ b/lib/types/thread-permission-types.test.js
@@ -4,13 +4,54 @@
   configurableCommunityPermissions,
   universalCommunityPermissions,
   userSurfacedPermissions,
-  type UserSurfacedPermission,
   threadPermissions,
 } from './thread-permission-types.js';
 import { getRolePermissionBlobs } from '../permissions/thread-permissions.js';
 import { threadTypes } from '../types/thread-types-enum.js';
 import { deepDiff, values } from '../utils/objects.js';
 
+const getUniversalCommunityPermissionsBlob = () =>
+  Object.fromEntries(
+    universalCommunityPermissions.map(permission => [permission, true]),
+  );
+
+const addAllUniversalCommunityPermissions = (
+  permissionsBlob,
+  universalBlob,
+) => ({
+  ...permissionsBlob,
+  ...universalBlob,
+});
+
+const addAllConfigurableCommunityPermissions = permissionsBlob => ({
+  ...permissionsBlob,
+  ...Object.fromEntries(
+    values(configurableCommunityPermissions).flatMap(permissions =>
+      [...permissions].map(permission => [permission, true]),
+    ),
+  ),
+});
+
+const removeAllConfigurableCommunityPermissions = permissionsBlob => {
+  const allConfigurableCommunityPermissions = values(
+    configurableCommunityPermissions,
+  ).flatMap(permissions => [...permissions]);
+
+  return Object.fromEntries(
+    Object.entries(permissionsBlob).filter(
+      ([key]) => !allConfigurableCommunityPermissions.includes(key),
+    ),
+  );
+};
+
+const reconstructOriginalPermissionsBlob = (
+  permissionsBlob,
+  permissionsToAdd,
+) => ({
+  ...permissionsBlob,
+  ...Object.fromEntries(permissionsToAdd.map(permission => [permission, true])),
+});
+
 describe('Community Announcement Root', () => {
   it('should find Member permissions from getRolePermissionBlobs and user-surfaced permissions to be equal', () => {
     const { Members: membersPermissionBlob } = getRolePermissionBlobs(
@@ -34,30 +75,70 @@
     expect(
       deepDiff(membersPermissionBlob, membersPermissionsConstructedBlob),
     ).toEqual({});
+    expect(
+      deepDiff(membersPermissionsConstructedBlob, membersPermissionBlob),
+    ).toEqual({});
   });
 
-  it('should find Admin permissions from getRolePermissionBlobs and user-surfaced permissions to be equal', () => {
-    const adminsPermissionBlob =
-      getRolePermissionBlobs(threadTypes.COMMUNITY_ANNOUNCEMENT_ROOT).Admins ??
-      {};
-
-    const adminsPermissionsConstructed = [
-      ...values(userSurfacedPermissions)
-        .map((permission: UserSurfacedPermission) => [
-          ...configurableCommunityPermissions[permission],
-        ])
-        .flat(),
-      ...universalCommunityPermissions,
+  it('should find Member permissions to be equal before and after adding permissions', () => {
+    const { Members: membersPermissionBlob } = getRolePermissionBlobs(
+      threadTypes.COMMUNITY_ANNOUNCEMENT_ROOT,
+    );
+    const universalCommunityPermissionsBlob =
+      getUniversalCommunityPermissionsBlob();
+
+    const constructedMembersPermissionsBlob = membersPermissionBlob;
+    expect(
+      deepDiff(constructedMembersPermissionsBlob, membersPermissionBlob),
+    ).toEqual({});
+
+    // Add all universal community permissions
+    const constructedBlobWithUniversalPermissions =
+      addAllUniversalCommunityPermissions(
+        constructedMembersPermissionsBlob,
+        universalCommunityPermissionsBlob,
+      );
+    expect(
+      deepDiff(constructedBlobWithUniversalPermissions, membersPermissionBlob),
+    ).toEqual({});
+
+    // Add all configurable community permissions.
+    const constructedBlobWithConfigurablePermissions =
+      addAllConfigurableCommunityPermissions(
+        constructedBlobWithUniversalPermissions,
+      );
+
+    // Remove all configurable community permissions
+    const constructedBlobWithoutConfigurablePermissions =
+      removeAllConfigurableCommunityPermissions(
+        constructedBlobWithConfigurablePermissions,
+      );
+
+    expect(
+      deepDiff(
+        constructedBlobWithoutConfigurablePermissions,
+        universalCommunityPermissionsBlob,
+      ),
+    ).toEqual({});
+
+    // Add the original user-surfaced permissions back to the Members blob
+    const originalUserSurfacedPermissions = [
+      ...configurableCommunityPermissions[userSurfacedPermissions.ADD_MEMBERS],
+      ...configurableCommunityPermissions[
+        userSurfacedPermissions.REACT_TO_MESSAGES
+      ],
+      ...configurableCommunityPermissions[
+        userSurfacedPermissions.EDIT_MESSAGES
+      ],
     ];
 
-    const adminsPermissionsConstructedBlob = Object.fromEntries(
-      adminsPermissionsConstructed.map(permission => [permission, true]),
+    const reconstructedBlob = reconstructOriginalPermissionsBlob(
+      constructedBlobWithoutConfigurablePermissions,
+      originalUserSurfacedPermissions,
     );
 
-    // Context: https://phab.comm.dev/D8478#inline-55680
-    expect(
-      deepDiff(adminsPermissionBlob, adminsPermissionsConstructedBlob),
-    ).toEqual({ descendant_voiced: true });
+    expect(deepDiff(reconstructedBlob, membersPermissionBlob)).toEqual({});
+    expect(deepDiff(membersPermissionBlob, reconstructedBlob)).toEqual({});
   });
 });
 
@@ -91,5 +172,76 @@
     expect(
       deepDiff(membersPermissionBlob, membersPermissionsConstructedBlob),
     ).toEqual({});
+    expect(
+      deepDiff(membersPermissionsConstructedBlob, membersPermissionBlob),
+    ).toEqual({});
+  });
+
+  it('should find Member permissions to be equal before and after adding permissions', () => {
+    const { Members: membersPermissionBlob } = getRolePermissionBlobs(
+      threadTypes.COMMUNITY_ROOT,
+    );
+    const universalCommunityPermissionsBlob =
+      getUniversalCommunityPermissionsBlob();
+
+    const constructedMembersPermissionsBlob = membersPermissionBlob;
+    expect(
+      deepDiff(constructedMembersPermissionsBlob, membersPermissionBlob),
+    ).toEqual({});
+
+    // Add all universal community permissions
+    const constructedBlobWithUniversalPermissions =
+      addAllUniversalCommunityPermissions(
+        constructedMembersPermissionsBlob,
+        universalCommunityPermissionsBlob,
+      );
+    expect(
+      deepDiff(constructedBlobWithUniversalPermissions, membersPermissionBlob),
+    ).toEqual({});
+
+    // Add all configurable community permissions.
+    const constructedBlobWithConfigurablePermissions =
+      addAllConfigurableCommunityPermissions(
+        constructedBlobWithUniversalPermissions,
+      );
+
+    // Remove all configurable community permissions
+    const constructedBlobWithoutConfigurablePermissions =
+      removeAllConfigurableCommunityPermissions(
+        constructedBlobWithConfigurablePermissions,
+      );
+
+    expect(
+      deepDiff(
+        constructedBlobWithoutConfigurablePermissions,
+        universalCommunityPermissionsBlob,
+      ),
+    ).toEqual({});
+
+    // Add the original user-surfaced permissions back to the Members blob
+    const originalUserSurfacedPermissions = [
+      ...configurableCommunityPermissions[userSurfacedPermissions.ADD_MEMBERS],
+      ...configurableCommunityPermissions[
+        userSurfacedPermissions.REACT_TO_MESSAGES
+      ],
+      ...configurableCommunityPermissions[
+        userSurfacedPermissions.EDIT_MESSAGES
+      ],
+      ...configurableCommunityPermissions[
+        userSurfacedPermissions.CREATE_AND_EDIT_CHANNELS
+      ],
+      ...configurableCommunityPermissions[
+        userSurfacedPermissions.EDIT_CALENDAR
+      ],
+    ];
+
+    const reconstructedBlob = reconstructOriginalPermissionsBlob(
+      constructedBlobWithoutConfigurablePermissions,
+      originalUserSurfacedPermissions,
+    );
+    reconstructedBlob[threadPermissions.VOICED] = true;
+
+    expect(deepDiff(reconstructedBlob, membersPermissionBlob)).toEqual({});
+    expect(deepDiff(membersPermissionBlob, reconstructedBlob)).toEqual({});
   });
 });
diff --git a/lib/utils/migration-utils.js b/lib/utils/migration-utils.js
--- a/lib/utils/migration-utils.js
+++ b/lib/utils/migration-utils.js
@@ -130,6 +130,50 @@
   threadPermissionPropagationPrefixes.DESCENDANT +
     threadPermissionFilterPrefixes.OPEN +
     threadPermissions.VOICED,
+
+  threadPermissions.JOIN_THREAD,
+
+  threadPermissionPropagationPrefixes.DESCENDANT +
+    threadPermissions.EDIT_ENTRIES,
+
+  threadPermissionPropagationPrefixes.DESCENDANT +
+    threadPermissions.EDIT_THREAD_NAME,
+  threadPermissionPropagationPrefixes.DESCENDANT +
+    threadPermissions.EDIT_THREAD_DESCRIPTION,
+  threadPermissionPropagationPrefixes.DESCENDANT +
+    threadPermissions.EDIT_THREAD_COLOR,
+  threadPermissionPropagationPrefixes.DESCENDANT +
+    threadPermissionFilterPrefixes.TOP_LEVEL +
+    threadPermissions.CREATE_SUBCHANNELS,
+  threadPermissionPropagationPrefixes.DESCENDANT +
+    threadPermissions.EDIT_THREAD_AVATAR,
+  threadPermissionPropagationPrefixes.DESCENDANT +
+    threadPermissionFilterPrefixes.TOP_LEVEL +
+    threadPermissions.CREATE_SIDEBARS,
+
+  threadPermissionPropagationPrefixes.DESCENDANT +
+    threadPermissions.ADD_MEMBERS,
+
+  threadPermissionPropagationPrefixes.DESCENDANT +
+    threadPermissions.REMOVE_MEMBERS,
+
+  threadPermissionPropagationPrefixes.DESCENDANT +
+    threadPermissions.CHANGE_ROLE,
+
+  threadPermissionPropagationPrefixes.DESCENDANT +
+    threadPermissions.EDIT_PERMISSIONS,
+
+  threadPermissionPropagationPrefixes.DESCENDANT +
+    threadPermissions.MANAGE_PINS,
+
+  threadPermissionPropagationPrefixes.DESCENDANT +
+    threadPermissions.REACT_TO_MESSAGE,
+
+  threadPermissionPropagationPrefixes.DESCENDANT +
+    threadPermissions.EDIT_MESSAGE,
+
+  threadPermissionPropagationPrefixes.DESCENDANT +
+    threadPermissions.MANAGE_INVITE_LINKS,
 ];
 
 export {