I noticed when flying around in a 1.13 world, I would hit weird pockets where the light levels would drop from 15 to 0.

I tried to replicate this in vanilla ... and I could not find any of these pockets. I even tried with a world that has the exact same seed, and I teleported myself to the exact same positions, and these pockets did not exists. I flew around for a few minutes and could not find any of these pockets.

I deleted my test server folder, ran buildtools to get the latest build " CraftBukkit version git-Spigot-69774b3-549d9b0 (MC: 1.13)" I started this fresh new server up with 0 plugins, and I did not modify ANY files what so ever. 

I have run server 1.12.2 test servers as well, and have not seen this bug before. 

Seed: [-5549153144651268952]

Position: 

-Normal Light: -620.81, 91.13, 875.74

-Dropped Light Level: -622.57, 91.13, 876,94

I have attached a few pictures to show that the light levels are dropping. I also including a few pictures where Im looking up at the sky to show that there are no blocks above me.