Expected Behavior

Actual Behavior

Reproduction Steps

1. Activate in the smooth light in graphics options

2. Choose one of the following blocks
   
   (It can be any slab or stair, the piston must be extended)

3. Place light

4. Lock yourself in a 1x2x1 where the light arrives and leave the chosen block as a roof

This mod is only for modifying the light engine, not the client rendering system.