I have a Ubuntu 12.10 server with an nginx user that I use to edit a crontab file. Periodically (maybe once every few hours? it's hard to tell), I notice that edits I have made as the nginx user have been deleted, and when I type crontab -e my last changes have disappeared. Once I make the changes again and save, the new file installs correctly, and the jobs run successfully until it reverts again at some stage in the future.
I am not a server admin expert, so I guess I'm asking what the best way to debug something like this is? Or if this is a common problem what the usual mistakes are that I might be making.