Minimize downstream effects of storage sync

ts/models/conversations.ts

@@ -1230,6 +1230,9 @@ export class ConversationModel extends window.Backbone.Model<
     const isLocalAction = !fromSync && !viaStorageServiceSync;
     const ourConversationId = window.ConversationController.getOurConversationId();
 
+    const currentMessageRequestState = this.get('messageRequestResponseType');
+    const didResponseChange = response !== currentMessageRequestState;
+
     // Apply message request response locally
     this.set({
       messageRequestResponseType: response,
@@ -1240,7 +1243,9 @@ export class ConversationModel extends window.Backbone.Model<
       this.unblock({ viaStorageServiceSync });
       this.enableProfileSharing({ viaStorageServiceSync });
 
-      await this.handleReadAndDownloadAttachments({ isLocalAction });
+      if (didResponseChange) {
+        await this.handleReadAndDownloadAttachments({ isLocalAction });
+      }
 
       if (isLocalAction) {
         if (this.isGroupV1() || this.isPrivate()) {

ts/services/storageRecordOps.ts

@@ -457,12 +457,19 @@ export async function mergeGroupV2Record(
 
   updateConversation(conversation.attributes);
 
+  const isGroupNewToUs = !isNumber(conversation.get('revision'));
   const isFirstSync = !isNumber(window.storage.get('manifestVersion'));
   const dropInitialJoinMessage = isFirstSync;
-  waitThenMaybeUpdateGroup({
-    conversation,
-    dropInitialJoinMessage,
-  });
+
+  // We don't need to update GroupV2 groups all the time. We fetch group state the first
+  //   time we hear about these groups, from then on we rely on incoming messages or
+  //   the user opening that conversation.
+  if (isGroupNewToUs) {
+    waitThenMaybeUpdateGroup({
+      conversation,
+      dropInitialJoinMessage,
+    });
+  }
 
   return hasPendingChanges;
 }