Having the same issue using Voyager with sh.itjust.works.

Happened a few months ago. It was an instance problem. They have a matrix channel for support but for some reason I can't post on it (dunno why, I barely participated on it once to tell about the issue and later I found I couldn't send messages anymore). I guess they'll solve it sooner or later.

I sometimes get it if I hide too many posts so it's kinda my gauge of time to get off Lemmy and do something.

Currently having this problem and it persists no matter what device or client I use

I think I know what you are talking about. I think it has to do with unstable/slow internet. Usually resolves after closing the app and waiting a bit.