I ran into this issue recently. I have created a linux service on Ubuntu, defined the StandardOutput to redirect logging to a file and anytime I restarted the service the log file didn’t update.

The first problem was that the logfile actually did update but it updated from the beginning of the file keeping the older lines and updatig the logfile gradually which is a very weird behaviour I would say.

The way this was fixed is that I have changed the StandardOutput definition in my service file from:

StandardOutput=file:/var/log/application.log

to

StandardOutput=append:/var/log/application.log

This means if the file doesn’t exists it will be created if it does exits it will just append the new log lines to the existing file instead of update the file from the very beginning causing confusion.