diff --git a/keyserver/src/fetchers/message-fetchers.js b/keyserver/src/fetchers/message-fetchers.js
--- a/keyserver/src/fetchers/message-fetchers.js
+++ b/keyserver/src/fetchers/message-fetchers.js
@@ -6,6 +6,7 @@
   sortMessageInfoList,
   shimUnsupportedRawMessageInfos,
   isInvalidSidebarSource,
+  isUnableToBeRenderedIndependently,
 } from 'lib/shared/message-utils.js';
 import { messageSpecs } from 'lib/shared/messages/message-specs.js';
 import { getNotifCollapseKey } from 'lib/shared/notif-utils.js';
@@ -890,10 +891,17 @@
   >();
   for (const message of parsedResults) {
     const { rawMessageInfo } = message;
-    if (isInvalidSidebarSource(rawMessageInfo)) {
+    if (isUnableToBeRenderedIndependently(rawMessageInfo)) {
       continue;
     }
     invariant(rawMessageInfo.id, 'rawMessageInfo.id should not be null');
+    // Flow fails to refine types correctly since
+    // isUnableToBeRenderedIndependently introspects into a message spec
+    // instead of directly checking message types. We use "continue" to avoid
+    // invalid messages, but Flow doesn't recognize this. The
+    // alternative is to check against every message type, but that defeats
+    // the purpose of a 'single source of truth.'
+    // $FlowFixMe
     rawMessageInfoMap.set(rawMessageInfo.id, rawMessageInfo);
   }
 
diff --git a/lib/shared/message-utils.js b/lib/shared/message-utils.js
--- a/lib/shared/message-utils.js
+++ b/lib/shared/message-utils.js
@@ -669,6 +669,12 @@
   return !messageSpecs[message.type].canBePinned;
 }
 
+function isUnableToBeRenderedIndependently(
+  message: RawMessageInfo | MessageInfo,
+): boolean {
+  return !messageSpecs[message.type].canBeRenderedIndependently;
+}
+
 export {
   localIDPrefix,
   messageKey,
@@ -700,4 +706,5 @@
   useNextLocalID,
   isInvalidSidebarSource,
   isInvalidPinSource,
+  isUnableToBeRenderedIndependently,
 };
diff --git a/lib/shared/message-utils.test.js b/lib/shared/message-utils.test.js
--- a/lib/shared/message-utils.test.js
+++ b/lib/shared/message-utils.test.js
@@ -1,6 +1,10 @@
 // @flow
 
-import { isInvalidSidebarSource, isInvalidPinSource } from './message-utils.js';
+import {
+  isInvalidSidebarSource,
+  isInvalidPinSource,
+  isUnableToBeRenderedIndependently,
+} from './message-utils.js';
 import { messageSpecs } from '../shared/messages/message-specs.js';
 import { messageTypes } from '../types/message-types-enum.js';
 import type { RawSidebarSourceMessageInfo } from '../types/message-types.js';
@@ -730,20 +734,26 @@
     expect(canBePinned).toBe(false);
   });
 
-  describe('canBeRenderedIndependently', () => {
+  describe('isUnableToBeRenderedIndependently & canBeRenderedIndependently', () => {
     it('should return false for RawReactionMessageInfo', () => {
       const messageSpec = messageSpecs[messageTypes.REACTION];
 
+      const shouldBeUnableToBeRenderedIndependently =
+        isUnableToBeRenderedIndependently(reactionMessageInfo);
       const canBeRenderedIndependently = messageSpec.canBeRenderedIndependently;
 
+      expect(shouldBeUnableToBeRenderedIndependently).toBe(true);
       expect(canBeRenderedIndependently).toBe(false);
     });
 
     it('should return false for RawEditMessageInfo', () => {
       const messageSpec = messageSpecs[messageTypes.EDIT_MESSAGE];
 
+      const shouldBeUnableToBeRenderedIndependently =
+        isUnableToBeRenderedIndependently(editMessageInfo);
       const canBeRenderedIndependently = messageSpec.canBeRenderedIndependently;
 
+      expect(shouldBeUnableToBeRenderedIndependently).toBe(true);
       expect(canBeRenderedIndependently).toBe(false);
     });
   });