Latest messages are shown only for a split second, then everything to yesterdays latest post disappears

[MojoQ]

Steps to reproduce

Switch from another room to our private room PBX Crowd (inhabitated by 28 users).

Outcome

What did you expect?

I can see all the messages, including the latest messages from today

What happened instead?

Todays messages are only shown for a split second, then they disappear.
The last message I see is the latest message from yesterday (04. April 13:32) and the Emoji-Reactions to it.

I get pop-ups for new messages. All other rooms work. I updated to the latest version via Discover. I killed the process and restarted Element. I rebooted the PC. I left the room and got re-invited. The problem persists.

Operating system

Operating System: Kubuntu 22.04 KDE Plasma Version: 5.24.7 KDE Frameworks Version: 5.92.0 Qt Version: 5.15.3 Kernel Version: 5.15.0-101-generic (64-bit) Graphics Platform: X11 Processors: 12 × Intel® Core™ i7-9850H CPU @ 2.60GHz Memory: 31.1 GiB of RAM Graphics Processor: Mesa Intel® UHD Graphics 630

Application version

1.11.63

How did you install the app?

From Discover (Package management)

Homeserver

matrix.teamfon.com matrix-synapse-py3/now 1.94.0

Will you send logs?

Yes

[MojoQ]

It magically solved itself throughout the day without further action by me.