Steps to reproduce:

1. User_A and User_B are both in the same community.
2. User_A sends several replies or mentions to User_B.
3. User_A sends one more message and then deletes it using the 'delete for everyone' option.
4. User_B checks the AC.

Actual result:

All mentions and replies in the AC are removed for User_B.

Expected result:

Mentions and replies should not be removed from the AC after the last message is deleted.

Additional info:

This issue is similar in group chats, with the exception that only replies are removed from the AC. Mentions are not removed and