Talk app for Android: no overview of previous chats for non-admins

for a few days we have been having problems with the Nextcloud Talk app for Android (the IOS app works as usual).
If the app is opened, an empty window appears, the overview of the previous chats is missing (the only thing we see are grey bars.).
If a new conversation is started and a contact is selected via the app, the older chats are available and telephony and chat functions work without any problems.
It is strange that users who are members of the “admin” group are not affected by this problem. Talk group restrictions are not set.

Has anyone had a similar experience and knows what’s causing it?

Many greetings