I tried opening the guide to check an achievement, when I suddenly couldn't open my guide anymore. I tried a few times, and each time the screen dims like its trying to open, then inevitably crashes and says there was an error. So I pressed the feedback button and got out of the game. Inside the feedback app, and everywhere else on the Xbox I can open the guide. But not in Minecraft. This just happened, and was fine all day. But this was a common bug in beta.

Edit: I feel like I should add, that at the time of this issue, I was hammering out a bunch of achievements in a pretty short amount of time. And some of them were lagging behind (taking a bit to actually unlock). I don't know if that will help with reproducing or not. But I hope it does. This desperately needs to be fixed.