Thread reply previews not showing consistently across users in Rocket.Chat

Description:

I tested thread reply previews between two accounts and found that the preview indicators (e.g. “X replied to this thread”) do not appear consistently for all users.

Steps to reproduce:

1. I used two Rocket.Chat accounts: Anshul and Dummy.

2. In a public channel, I created Thread 1 and Thread 2 (by replying to two separate messages).

3. Then I performed the following:

   Thread 2:

   Dummy replied: th2 hi 1

   Anshul replied: th2 hi 2

   Thread 1:

   Anshul replied: th1 hi 1

   Dummy replied: th1 hi 2

Expected behavior:

All users should see thread reply previews under the original message, regardless of who replied or viewed it. The previews should always appear if any reply exists.

Actual behavior:

As Anshul:

✅ I see reply previews for both Thread 1 and Thread 2, showing all replies.

As Dummy:

✅ I only see preview for:

    My own reply to Thread 2

    Anshul's reply to Thread 1

❌ I do not see:

    Anshul’s reply to Thread 2

    My own reply to Thread 1

Server Setup Information:

• Version of Rocket.Chat Server: open.rocket.chat
• License Type:
• Number of Users:
• Operating System:
• Deployment Method:
• Number of Running Instances:
• DB Replicaset Oplog:
• NodeJS Version:
• MongoDB Version:

Client Setup Information

• Desktop App or Browser Version: Firefox 136.0.1 (64-bit)
• Operating System: Ubuntu 24.04.2 LTS

Additional context

Relevant logs:

Start by reproducing the behavior with the two-account, two-thread scenario in a public channel using Firefox on Ubuntu. Trace the thread reply preview handling from the affected client entry point and compare what each account receives; done means every user sees all existing reply previews under the original message.