Priority glitch: which patch?

The change seems too specific to be an editing mistake. There are eight different F7s that are changed to B7s and they are all very close together. It seems more likely that it's a side effect of an editing program or something like that. Unless it was an attempted fix at something else and I never bothered to revert it.

What I'm trying to do is narrow down its effects to try and figure out its intent. If my findings are correct, the maps that are affected are all the external maps of Fanatics' Tower and Zozo. So what I'm wondering is if there was some kind of intent based on either layering priority or NPC interaction or anything similar.