Indeed, that all looks fairly innocuous. Just in case, you are sure that you didn’t just accidentially kill or killall rclone or bash?

Perhaps wrapping the script in strace might help debug where the offending signal is coming from.

TimeoutStopSec applies to the ExecStop command, TimeoutStartSec would be the culprit here. I’m not sure why there would be a default timeout of specifically 1:39 minutes though.

Does your script fork at some point (and might exit before the rsync job is completed)? Because then you need to use Type=forking instead of simple or oneshot, otherwise systemd will start trying to clean up child processes when the script exits.

Edit: Actually considering the time span involved Type=forking will not solve your issue because it will timeout, if this is the problem you need to change your script to not do that.

To be fair this also happened to Eagle Dynamics, developer of DCS, the other “realistic” flight sim that players take far too seriously. Except there it was a Dev that got arrested in Georgia and extradited to the US…