I didn't use any custom conferences at all and I'm not using a teambuilder team.
I did, however, press the button to "create a random schedule" back in the preseason menu. Wonder if that has anything to do with it?
I mean...the game is literally stuck in Week 15. You can't advance forward or sim any games or do anything, but look at stats and standings. It's 100% broken at the moment. I'm at work now, but when I get a chance later tonight I'll boot it back up and try again. Luckily I turned auto save off when I tried to sim ahead, so my save file is still in week 8.