Hi. I get this on a regular basis, but not so "repeatedly" as to be irritating, when I also know neither myself or anyone else has changed the file. I've guessed that it's some sort of activity on the web server, say if there's a back-up activity or the host upgrades any of the software. I'm no web server expert - and sometimes I've wondered if when a surfer visits the page and/or a script executes there's a 'touch' on the file though now I really am just guessing.
I don't think there is any way to stop the message I'm afraid other than perhaps syncing (which could be onerous if it's a big site) each time you decide to have a session working on the site, before you do any work. It's maybe something to ask your host about in terms of activity on the server, what might be causing it to touch the files.
(Look up: 'touch (Unix)' on wikipeadia)
Hope this helps/reassures.
