Everytime a weaponsmith like this one generate it comes with 4 blocks of air on its side that probably should not be there and instead of it, the natural terrain of the place it generate should cover the space.

Reproduce:
1. Create a new world.
2. Search for a village with this structure.
3. Look at it.

Observed Results:
There are blocks of air on the ground level of the structure.

Expected Results:
Terrain from the place the structure is found in should cover the space.

Here are some footages of the bug:

seed example with this weaponsmith: 63597105496628543, coordinates: x37 y71 z320 (this village has ALOT of these), seed comes from MCPE-177558.