To my memory of previous versions, when a player is in bed, their name will show up above the bed.

However, I noticed in this scenario, the player's name appears below the bed.

Though I'm not exactly certain what causes it, it was on a multiplayer server with no mods/plugins. However, this was the scenario where this occurred.
1. Place a bed on two blocks, then break the two supporting blocks.
2. In this case, there was a wall snugly encasing the bed on three sides, and a one block high space above the bed.
3. The player's nameplate who's in the bed will appear half a block's length beneath the floating bed.
*On a side note, when day arrives, the bed ejects the occupant and puts the occupant into the roof, who will take suffocation damage. Not sure if intentional.
*On another side note, the bed's texture is textured wrong, but that's been reported already.