It's not a bug. It's supposed to not let you switch rooms while the block is dropping. That's why I made the idol turn red. I should probably make it more obvious.
Oh yeah, so that happened and seemed fine, totally got it, but then on maybe the third or fourth visit to that activity in the one playthrough it went red and stayed red for the remainder of the five minutes. Maybe I hit something other than 'back' and that locked it in red?