diff --git a/packages/data-schemas/src/methods/chatProject.ts b/packages/data-schemas/src/methods/chatProject.ts
index d2a98036c7..e38f1587f7 100644
--- a/packages/data-schemas/src/methods/chatProject.ts
+++ b/packages/data-schemas/src/methods/chatProject.ts
@@ -300,19 +300,19 @@ export function createChatProjectMethods(mongoose: typeof import('mongoose')): C
     );
   }
 
-  function forceConversationRetention(
+  async function forceConversationRetention(
     user: string,
     conversationId: string,
     interfaceConfig?: AppConfig['interfaceConfig'],
   ): Promise<void> {
     if (!isForcedTemporaryRetention(interfaceConfig?.retentionMode)) {
-      return Promise.resolve();
+      return;
     }
     const Conversation = mongoose.models.Conversation as Model<IConversation>;
     const Message = mongoose.models.Message as Model<IMessage>;
     const SharedLink = mongoose.models.SharedLink as Model<ISharedLink>;
     const File = mongoose.models.File as Model<IMongoFile>;
-    return cascadeForcedConversationRetention(
+    await cascadeForcedConversationRetention(
       Conversation,
       Message,
       SharedLink,
diff --git a/packages/data-schemas/src/methods/message.spec.ts b/packages/data-schemas/src/methods/message.spec.ts
index 4d6497e2ed..87b1dcf1a2 100644
--- a/packages/data-schemas/src/methods/message.spec.ts
+++ b/packages/data-schemas/src/methods/message.spec.ts
@@ -1200,6 +1200,41 @@ describe('Message Operations', () => {
       expect(refreshed?.lastConversationId ?? null).toBeNull();
     });
 
+    it('refreshes owning project stats when a message-only save converts a project chat', async () => {
+      const ChatProject = mongoose.models.ChatProject as mongoose.Model<IChatProject>;
+      await ChatProject.deleteMany({});
+      const conversationId = uuidv4();
+      const project = await ChatProject.create({
+        name: 'Ephemeral Project',
+        user: 'user123',
+        conversationCount: 1,
+        lastConversationId: conversationId,
+        lastConversationAt: new Date(),
+      });
+      const projectId = project._id!.toString();
+      await Conversation().create({
+        conversationId,
+        user: 'user123',
+        endpoint: 'openAI',
+        title: 'Project chat',
+        isTemporary: false,
+        chatProjectId: projectId,
+      });
+
+      await saveMessage(
+        {
+          userId: 'user123',
+          interfaceConfig: { temporaryChatRetention: 24, retentionMode: RetentionMode.EPHEMERAL },
+        },
+        { messageId: uuidv4(), conversationId, text: 'branch', user: 'user123' },
+        { context: 'branch', capExpiryToConversation: true },
+      );
+
+      const refreshed = await ChatProject.findById(projectId).lean<IChatProject>();
+      expect(refreshed?.conversationCount).toBe(0);
+      expect(refreshed?.lastConversationId ?? null).toBeNull();
+    });
+
     it('converts a permanent conversation and its messages without a messageId (tag write)', async () => {
       const conversationId = uuidv4();
       await Conversation().create({
diff --git a/packages/data-schemas/src/methods/message.ts b/packages/data-schemas/src/methods/message.ts
index 884061b0c4..cbbe4f59bb 100644
--- a/packages/data-schemas/src/methods/message.ts
+++ b/packages/data-schemas/src/methods/message.ts
@@ -215,7 +215,7 @@ export function createMessageMethods(mongoose: typeof import('mongoose')): Messa
         const Conversation = mongoose.models.Conversation as Model<IConversation>;
         const SharedLink = mongoose.models.SharedLink as Model<ISharedLink>;
         const File = mongoose.models.File as Model<IMongoFile>;
-        await cascadeForcedConversationRetention(
+        const convertedParent = await cascadeForcedConversationRetention(
           Conversation,
           Message,
           SharedLink,
@@ -224,6 +224,16 @@ export function createMessageMethods(mongoose: typeof import('mongoose')): Messa
           conversationId,
           cascadeExpiredAt,
         );
+        /**
+         * Message-only writes (branch/artifact/abort saves) have no `saveConvo` afterward to
+         * recompute project stats, so when the cascade just hid a project chat the cached
+         * count/lastConversationId must be refreshed here.
+         */
+        if (convertedParent) {
+          await refreshForcedRetentionProjectStats(userId, {
+            conversationId,
+          } as FilterQuery<IConversation>);
+        }
       }
 
       return message.toObject();
@@ -467,7 +477,7 @@ export function createMessageMethods(mongoose: typeof import('mongoose')): Messa
         },
       ]);
     }
-    await cascadeForcedConversationRetention(
+    const convertedParent = await cascadeForcedConversationRetention(
       Conversation,
       Message,
       SharedLink,
@@ -476,9 +486,11 @@ export function createMessageMethods(mongoose: typeof import('mongoose')): Messa
       conversationId,
       forcedExpiredAt,
     );
-    await refreshForcedRetentionProjectStats(userId, {
-      conversationId,
-    } as FilterQuery<IConversation>);
+    if (convertedParent) {
+      await refreshForcedRetentionProjectStats(userId, {
+        conversationId,
+      } as FilterQuery<IConversation>);
+    }
   }
 
   /**
diff --git a/packages/data-schemas/src/utils/retention.ts b/packages/data-schemas/src/utils/retention.ts
index 81487c2df3..1f764a4fc1 100644
--- a/packages/data-schemas/src/utils/retention.ts
+++ b/packages/data-schemas/src/utils/retention.ts
@@ -224,7 +224,9 @@ export const capForcedRetentionToParent = async (
  * Converts or re-caps a parent conversation to the forced deadline and, when that first
  * brings the conversation into the forced window, backfills its lagging messages, shares, and
  * files. Shared by every forced-retention message-write path so a single conversation/message
- * rule is enforced regardless of which save touched the chat.
+ * rule is enforced regardless of which save touched the chat. Returns whether the parent row
+ * was converted, so callers can refresh caches (e.g. project stats) that a visibility flip
+ * invalidates.
  */
 export const cascadeForcedConversationRetention = async (
   Conversation: Model<IConversation>,
@@ -234,13 +236,13 @@ export const cascadeForcedConversationRetention = async (
   userId: string,
   conversationId: string,
   forcedExpiredAt: Date,
-): Promise<void> => {
+): Promise<boolean> => {
   const parent = await Conversation.findOne(
     { conversationId, user: userId },
     'isTemporary expiredAt',
   ).lean<RetentionFilterDocument | null>();
   if (parent == null) {
-    return;
+    return false;
   }
   const expiredAt = capForcedRetentionExpiry(parent.expiredAt, forcedExpiredAt);
   /**
@@ -255,12 +257,13 @@ export const cascadeForcedConversationRetention = async (
   await capConversationSharedLinks(SharedLink, userId, conversationId, expiredAt);
   await capConversationFiles(File, conversationId, expiredAt);
   if (!conversationNeedsForcedRetention(parent, expiredAt)) {
-    return;
+    return false;
   }
-  await Conversation.updateOne(
+  const convoResult = await Conversation.updateOne(
     { conversationId, user: userId, ...forcedRetentionGapFilter<IConversation>(expiredAt) },
     { $set: { isTemporary: true, expiredAt } },
   );
+  return (convoResult.modifiedCount ?? 0) > 0;
 };
 
 /**