NextCloud Sync Client (Windows) stops syncing regularly until restart

I’m having problems with the NextCloud Sync Client running on Windows Server 2019. I’m using the client to sync files between a dockerized NextCloud instance and a Windows Server 2019 VM. Every now and then (approximately once every 1-2 days), the Sync Client seems to run into an undefined state. It either hangs in “Synchronizing” state (the tray symbol is the blue sync icon) or the tray symbol is yellow, something along the lines of “The client is in an undefined state”. In both cases, new/updated/deletes files from the NextCloud instance are no longer processed by the Sync Client and the folders on the server quickly become outdated. I need to close the client and restart in order for it to start syncing again.

I don’t really know where to start debugging. I’ve seen the debug log option and I’ve exported the logs after the most recent occurrence of the issue. The log doesn’t seem to show any specifics as to why the client can no longer sync files. The only error which is shown is the following (which doesn’t seem relevant, because it occurs at a point of time where we know the client is already in the error state):

[ warning nextcloud.gui.folderwatcher C:\Users\sysadmin\AppData\Local\Temp\2\windows-8634\client-building\desktop\src\gui\folderwatcher_win.cpp:117 ]:	GetOverlappedResult error "WindowsError: 40: Der angegebene Netzwerkname ist nicht mehr verfügbar."

The log section in NextCloud web has the following error, but it appears before and after the point of time when I know the error happened, so it’s probably unrelated too:

Exception: Call to a member function inGroup() on null in file '/var/www/html/apps/files_sharing/lib/Notification/Notifier.php' line 195

I’m using NextCloud 23.0.0 in the official Docker container. The client version is 3.4.1.

Does anyone know where to start debugging this issue? What could cause the client to stop syncing altogether?