That’s interesting. I’ve not had that sort of issue. On my phone (Android), my son’s laptop (Windows) and my desktop (Arch Linux) the NextCloud clients all sync perfectly and run at start up. Granted, knowing that the Linux landscape is fractured, I wouldn’t be overly surprised if the client had issues on some flavors of Linux.
My apologies, I was not familiar with the difference. I’m going to have to test this when I am back at my system. Looking at the docs, it does seem to be experimental in Linux. But it seems odd that it would turn off automagically.