Some messages (seemingly threaded ones) disappear from the timeline

### Steps to reproduce

It's random, can't reproduce at will.

### Outcome

I'm seeing several instances of messages disappearing from the timeline. For the moment they are all threaded messages (not sure if it's related to that).
It affects only specific instances of eleweb (i.e. my desktop instance shows this bug, but if I log in from both [chat.element.io](http://chat.element.io/) or [develop.element.io](http://develop.element.io/) I don't see the bug).

### Operating system

_No response_

### Application version

_No response_

### How did you install the app?

_No response_

### Homeserver

_No response_

### Will you send logs?

Yes