Simply put, the game's bed based respawn system seems (seems) to be completely and totally non-functional at the moment. I make a bed. I place it in a room. Surrounding the bed is a 2x3 wide section of empty air, with solid walls all around, a solid floor underneath and the bed in the center. I sleep in the bed. Come morning, I throw myself in a nearby lake and drown. And BOOM! Back to the world spawn, with the game helpfully telling me that my home or bed is missing or obstructed.

I try other things. I try removing the floor. Nothing. I try adding torches. Nothing. Wider room? Nope. Door? Nada. No door? No dice. Only time I'm able to control my spawn is once, when my bed is on a floor below where I ended up respawning, and I respawn on a block of nether sand, directly above where my bed was, in a small enclosure surrounded by glass on all sides, with the exception of having a solid roof. What? Why on earth is THAT where I respawned? My bed wasn't even in there!