That is not an overlapping structure. This is:
Please note that there’s more than one piece in that ceiling. This is what you’d get on normal circumstances:
As @Mikey pointed out, that’s legal. This would be the illegal version tackled with the patch:
In this case, the fence foundations that are going through the normal foundations will be nuked. Stability shouldn’t be affected in most cases since the stability would rely on the remaining pieces.