Ok, I think I'm going insane. After the bridge merge I noticed that on my Xperia Play, rice is giving junk graphics on the sides where the black pillarboxes should be - in Mario 64 no less. Naturally I panicked... So I started going back, back, back to 2.1.0. Complete reinstall, complete clean build. Problem is still there. I'm going to keep going back in time...
Did I miss something or did rice always do this on the Xperia Play? I could have sworn I never had this problem before.