I had the same issue a few times and created a script to check every 15 minutes if the OS process is running or not and to start if needed.
I will check this evening in the logfile if the process has ben restarted again in the last couple of days.
I will post the script here also.
This issue happend with version 2.1.4 and I don’t know (did not check the logfile) if the problem was solved after the 2.1.5 update.