Candles can generate in the air in Ancient City due to missing blocks

Summary:
Candles and lanterns can generate in air in Ancient City due to missing blocks. It seems that this only happens in barracks.

Seed: -2292929805313073740
Coords: 1291 -46 -842
Coords: 851 -44 -698

Seed: -732078047
Coords: 498 -45 1199

Steps to reproduce:

1. Create a world with the specified seed.
2. Visit the specified coordinates.

Observed results:
Candles are in the air without any support.

Expected results:
Candles and lanterns will not be generated in the air.

Screenshots: