Priority glitch: which patch?

I found a glitch in my ROM wherein my party members pass underneath this NPC when standing on the tile below. I found the cause: in the area of D9/B62E, there are eight bytes that start with the value F7 and are changed to B7. I'm wondering if there's some patch that's responsible for that change, but I haven't been able to find it yet. I would really appreciate some help here, because I'm hesitant to just reverse that change without understanding the intent.