Cannot spawn close to bed if bed is surrounded by halfslabs

Yeah, so if you put halfslabs around your bed and then sleep in it, it's fine, you will awake on the halfslabs. But if you then die, you cannot spawn next to it. This is both weird and inconsistent.

How to reproduce? Place halfslabs all around the bed and do the same.

If there's sufficient room above the halfslabs (being at least 2 full blocks of free space), you should be able to spawn on the halfslabs.