I've never seen it change "untouched by human hands" although I suppose some virus or malware might've done it. I'd sure be suspicious about some of the other users that maybe were playing around and changed it, possibly accidentally.
I changed the IPv4 settings to use an IP address that I set. A few weeks later I was wondering why I couldn't connect to my MySQL server, and after attempting a few other fixes I spotted that it had reset to "Obtain an IP address automatically".
I have not changed these settings since I initially changed them. It had worked fine for about 2 weeks.
I need the IP address to always be the same, otherwise the users of the database will find that they can't use it.
I don't think that the other users of the system would have reset it, because they wouldn't know how to get to it / wouldn't have a reason to change it.
I think I may well just create a batch script to run periodically to avoid this, but is there a reason why this has happened? Windows Updates? An expiry time?