Steps to reproduce

1. Create a world on simulation distance 4, set render distance as low as possible, and make sure "beautiful skies" is toggled on in video settings.
2. Go about 20-40 blocks underground and run /fill ~~~ ~100 ~10 ~109 air.
3. Fly to the end of the tunnel and run the same command again.
4. Fly back to either end of the tunnel.
5. Set time to night.
6. Look down the tunnel and watch for a few minutes.

Expected result

You see blackness at the end.

Observed result

You see stars at the end of the tunnel.

I was exploring a cave system in my world and discovered these peculiar lights in the cave system not sure if this counts as a glitch but I didn't think it was interesting enough to report.