When exploring the new Ancient Cities in the 1.18.30 update, I came across patches of sculk veins floating in the air. I realized the sculk vein was on an invisible block. I knew it was a structure void block.

Since I like to explore the technical side of minecraft I knew the structure void block was a jigsaw block beforehand.

The jigsaw blocks that turn into structure voids are the ones used in the horizontal_wall structures and the ruin structures that connect to the walls.

The jigsaw should turn into air instead of a structure void.

Expected Results:

     Turns into air block.

Observed Results:

     Turns into structure_void creating an invisible block that can't be destroyed but can be interacted with tools and shows a highlight.

How to Reproduce:

     1. Go to an Ancient City.

     2. Visit a ruin (medium_pillar, barracks, sauna, etc).

     3. Look at the position a jigsaw block was in the structure file. (Most easily found by floating sculk veins that spawned attached to the jigsaw, or an empty space where there is flowing water.)