Ok, hear me out with this possibility... My Sinn 104 gained maybe a second a day before I wore it on a flight to Chile this past summer. When I arrived there I went to advance the time + 2 hours for the time change and found the crown very hard to unscrew. Then, within a day, the watch was gaining 15 seconds a day. It has remained the same ever since. Can airplane travel cause a watch to have these problems? the 104 is considered an aviator watch, to boot... Watch is nine months old. It hasn’t been magnetized.
Thanks for any input as to why the watch is behaving like this, literally overnight.