Synchronisation of read articles across multiple devices is not reliable

I use the app on two devices (Samsung Galaxy A71 and Galaxy Tab A8). When I read articles on one device and then want to read more unread articles on the other device, I often get articles that I have already read on the first device displayed again as new.

In the Nextcloud backend, the affected articles are correctly marked as read. Emptying the cache on the second device reliably helps, then the status is synchronised again.

This is feasible, but no good user experience. I thought about always emptying the cache as soon as the app is displayed. This seems a bit aggressive to me, but should solve my specific problem.

Now the question is whether I have a wrong configuration of the app or whether this is a general problem.

Is there anything I can provide additionally to my description?