Whole bed is lit up based solely on the head part

Steps to reproduce

1. Set brightness to 0 and time to night for more obvious results
2. Place a bed (and another optional one parallel for comparison)
3. Place a light source next to the head of one bed on either side
   → The foot of the bed is visually lit the same as the head of the bed
4. Move the light source next to the foot of the bed
   → The bed is less bright