u/Ok-Acanthisitta-6622

I'm following the regular guide everyone uses for catching Entei and Raikou, and I've noticed something strange about the roaming behavior:

I was in route 32, moving in one section of grass, far from any transition or area change. I checked the Pokedex map when I entered, the Entei was there in the same area as me. After a few encounters (of which I ran from) and a phone call from a trainer, Entei moved to another route.

I'm struggling to find any info about a situation like this, could it be that common knowledge on this subject here is missing info? I'm not super into pokemon like some people, so forgive me if this is a super common thing.

I know there's a full collection out there, but that's for an older badge homebrew, and doesn't support categories, and has no category icons. Has someone already made a collection for Anemone3DS with the category icons set up?