It may have been updating metadata, rather than updating Roon itself. I notice that there’s a burst of activity from my Roon Core every 24 hours or so. It’s over within 10 minutes, but I can imagine that if you’re cursed with a slow internet connection then you might well notice it.
Set everything to update manually. Then get up at 01.00AM, start the updates and pray for the best (there is no update in the software world today that doesn’t break something). After doing it for 3 or 4 times, you’ll probably end up going to some church and pray that something, someone, somewhere will bring some sense in today’s developer minds!