When a bed's state is converted to numerical meta and vice-versa (getMetaFromState and getStateFromMeta in MCP) it stores or reads the 'occupied' flag only if the block is the head end of the bed, but when the block is converted to its 'actual state' for rendering (getActualState in MCP) it will only read the occupied flag if the block is the foot end of the bed.
This causes the following issues:
The renderer can never see the actual occupied state of beds, so it is not accessible in block state files.
Can break any other code which reads the state through getActualState - I'm not sure if there is any such code but there easily could be.
Comments

Is this still an issue in the most recent versions (currently that is 1.12) of Minecraft? If so, please update the affected versions and help us keeping this ticket updated from time to time. If you are the owner/reporter of this ticket, you can modify the affected version(s) yourself.