TL;DR: Touch ID stopped prompting me in 1P b2 on iOS b3, even after a device restart. After updating to b3, it still wouldn't prompt me, but now it works. I'm reporting this since I wasn't sure if its broken-ness carrying over from b2 to b3 is an issue.
Touch ID is enabled and set to request my fingerprint after exiting 1P or leaving 1P idle for 2 minutes. In b2, Touch ID stopped working entirely, I had to reenter my MP every time I exited the app, even if I opened it one second later.
Then I received the b3 prompt and upgraded. Touch ID still misbehaved, my MP was requested immediately, wouldn't see a Touch ID prompt. Once I disabled and reenabled Touch ID with the same settings, it is now working.