diff --git a/lib/shared/thread-utils.js b/lib/shared/thread-utils.js
--- a/lib/shared/thread-utils.js
+++ b/lib/shared/thread-utils.js
@@ -3,6 +3,7 @@
 import invariant from 'invariant';
 import _find from 'lodash/fp/find.js';
 import _mapValues from 'lodash/fp/mapValues.js';
+import _omit from 'lodash/fp/omit.js';
 import _omitBy from 'lodash/fp/omitBy.js';
 import * as React from 'react';
 
@@ -903,7 +904,7 @@
     entries(rawThreadInfoWithoutSpecialRoles.roles).map(([key, role]) => [
       key,
       {
-        ...role,
+        ..._omit('isDefault')(role),
         specialRole: rolesWithFilteredThreadPermissions[key]?.specialRole,
       },
     ]),