Since Pre-3 and Pre-4 didnt adress any lighting issues, this should be existing there too.

After restarting the world, lighting will come back into the room i will add pictues of.

As you can see, its a simple skeleton spawner elevator to have them fall for the fall damage.

Both "pipes" to go up with the bubble elevator and where they drop down have a sky light level of 15, although there is blocks all around it (and i even filled diagonal spaces).

The block light level correctly is at 0, as none of the blocks emit light.