Say hypothetically, I'm gaining what appears to be "2 minutes" but without a seconds hand I can't be sure, maybe it's just under 2 minutes and let's say it's around 10-14 days. Gaining 100 seconds in say 12 days - averages out to only 8 seconds a day, which isn't that bad for an ultra thin watch. Eight seconds a day seems to be too small for a magnetism, which is why I didn't think it was a magnetization issue. I have a second JLC Master Ultra Thin with the 849 movement, that one seems to run fast, but not noticeably like the MUT 38. I'll try demagnetizing it the next time I'm in the city. Can't hurt.