The bug

Eight layers of snow can be stacked into a full cube block. However, despite being a full cube, sculk veins cannot be placed on the top or five sides of it, despite sculk veins being intended to adhere to any full cube.

How to reproduce

1. Stack up eight snow layers
2. Attempt to place sculk veins on each side of this block

Expected results

Placement would succeed.

Actual results

It fails completely.