Just curious, but are the settings retained when the key fob locks/unlocks?
Had a similar issue with my wifes expedition, she was primary driver,and we didnt changed anything between us when we drove as we are the same height, but when we'd take it in for service, the techs would move the seats, mirrors, pedals and wheels, then lock it when done. We'd always give them the spare key ring/foband so those settings would be set when they locked it with that fob. Fast forward to me taking my wife's rig for an errand, or needing to unlock it to get something quickly using the spare key, and everything would move back to that position. If I wasn't paying attention, or if my wife asked me late in the day, if I locked her car back up, and I inadvertently locked it with her fob again,, those new settings would be saved
Hoss