aircraft cfg file updates itself

Hi all,I have an odd issue that I'd like to understand:Some of my custom AI aircraft.cfg files get updated every time I start the sim. I've checked a couple of times but the previous and "updated" copy are identical so this is not an issue of FS adding some unspecified commands.Moreover, similar aircraft.cfg files of mine don't show this behavior at all yet I don't see any obvious differences in their structure.Has anyone ever encountered something similar? There doesn't appear to be any ill effect of this behavior but I'd prefer a "stable" date stamp to be better able to track the changes that I did myself.Cheers, Holger