I also have similar problems to the OP (@newtooctoprint) but in my experience it seems to be the underlying OS on my RPi losing connection to my WiFi router so the problem is either in Raspian (or whatever it's called these days) or OctoPi, not OctoPrint. Maybe check their support forums to see if answers have been found. I'm probably going to run a network cable across my basement from my router to my RPi to see if that solves my issue.
FWIW, one big indicator the problem on my setup is with the OS and not OctoPrint is the last time this happened to me OctoDash (which is a separate process to OctoPrint) was telling me an update was available (must have pinged the server before losing WiFi), yet I couldn't download the update until after I rebooted my RPi.
EDIT: Corrected auto-correct errors.