As an update,
We tried uninstalling and re-installing multiple times and restarting the machine multiple times, but after a day or two jobs.xml again would stop being updated. On a hunch I inactivated several inessential jobs with five minute interval triggers that I kept seeing being run at the times the file stopped being updated. Since that change it's been almost two weeks without seeing the error. I don't really know why it worked, but it seems like it has.
Thank you for the update. When I look at the log file again I see constant updates of "Jobs saved". We do log if any failure should occur during the actual saving but there is no trace here.
One thing that might be interesting for you to monitor is how we save Jobs. What we do is the following, in order;
1. place a temporary lock on the Save method
2. serialize (convert current list of Jobs to xml format) into a temp file called jobs.tmp.xml
3. delete the current "jobs.xml"
4. rename the jobs.tmp.xml to jobs.xml
5. release lock
The same object that is used to create the file is also used when you, for example, connect with a new Client. So, it would be very strange if the file is not updated while the newly connected Client can see the updates.
We do seldom update the Job instantly. Normally a minute after changes has been made.