Savanna cartographer shop has a hole in the floor

The savanna cartographer shop often generates with a hole in the middle of the floor.
(This is not new; I experienced it in 1.13 but never got around to documenting, and had trouble finding a reproducible example because of world generation changes between versions.)

Steps to reproduce

1. In 1.16.100, create a world with seed -54836576, with cheats on.
2. /tp @s 3505 70 -1907
3. Open the door and look at the floor.

1. In 1.18.12, create a world with seed 85035792, with cheats on.
2. /tp @s -947 92 -1888
3. Open the door and look at the floor.

Expected result

The floor is solid and complete.

Actual result

There is a missing block in the middle of the floor.