Previous Sent Messages are Missing After Ignoring the User

We have noticed a behaviour when the old messages from 1:1 chats are missing after the user gets ignored. The logout and login again helps and returns all messages. It happens time to time on multiple clients including Element as well. It looks like not all events will be sent by matrix which cause the missing messages after the user gets ignored which might be related to the timeline.

Steps to reproduce:
1. Create a 1:1 chat
2. Send multiple messages
3. User1 ignores User2
4. Previous sent messages are gone

P.S. our last testing session required around 20 attempts to reproduce the issue.

Start with the listed reproduction steps and trace timeline and event handling in the TypeScript SDK, since no file or test is named. Done means previously sent 1:1 messages remain visible after one user ignores the other, with a reliable regression check if the behavior can be reproduced.

Written by the indexing model from the issue text.