Patch is up, though the servers are currently down due to maintenance. Here's the new warning screen when you change a slider:
Interestingly, the warning pops for when you change ANY slider still, so although it does specify gameplay sliders, we aren't going to know which ones cut XP and which don't (if any) until maintenance is finished. And, in my case I'm going to have to, uh....improvise to find out since I've already completed the 1st inning path (and therefore cannot earn any more XP until the 2nd inning comes out).
Edit: Maintenance is already complete and things are back online.