It completely locked my drive on a Macbook Pro mid-2014. With no warning or user information, it simply wouldn't accept my password and could not log-in. I had to drop into recovery mode and use the terminal with some obscure commands from a forum post somewhere to unlock it ... talk about user friendly. Apple is really slipping in terms of QA here.
I had disk utility telling me that my unlock password both did and did not work, and I didn't want to move forward like that. Disk utility's password prompt would do the 'ya done fucked up' wiggle at the same time the main window below it loaded partition information.
Details: https://forums.developer.apple.com/thread/80174 (it had something to do with the preboot iirc, note that this wasn't on the beta but the actual release)