Well I thought of that, then I deleted all of the box BSPs and added a single new one, and had the same issue when putting them in a certain area. But then I realized there was a cone bsp touching the side of where i was placing the walls. So now that I think about it, this must have been the issue. I didn’t realize this would happen. I’ll try to reproduce the problem and see if converting to static mesh resolves it. For now this seems to be the resolution, thanks for the information 