more testing shows that you dont have to have just digged out the space, but the error doesnt always happen in that case. it always happens when you’ve just dug out the space and then placed the wall. furthermore, despite my original oddly specific situation, this seems to happen in any situation where you dig out sandstone next to any amount of sandstone and replace it with a sandstone wall, but it is more likely the more likely to happen the more neiboring sandstone there are, and always happens in the originally described situation.
