I posted this in the "stats reset" thread as well, but it may all be related:
I had a quick look at season mode, didn't even make it as far as starting the first event, backed out and played and different game entirely (GTA V). Went back into TGC a day later to find the "corrupt data" message that others have been getting with respect to season mode. Played a round on a tournament (not season mode), and went back to GTA V.
Opened up TGC the next day to find all my game settings were back to the default ones! I had to set the audio and display settings back to how I like them, set it to use left stick, and change my golfer to look the way I like him to.
Incidentally, I'm sure there's a problem with my in-game stats and Xbox achievements not updating, if at all. But that's been ongoing for ages.
Obviously I'm not gonna touch season mode until I'm sure it'll work fine.
Xbox gamertag is - CongoGB
Thanks guys