So I have a little doubt that I feel I should have answered before but I haven't, so I'm sorry if it sounds stupid, but, do wild pokémon appear on a route depending on the types of your first pokémon? I mean, taking into account the species availables in a route, the percentages of each one seem to be rigged based on the types of your lead. For example, let's say Im on the Alleyway on Obsidia Ward, and I've got a Bug mon to train, then suddenly, dark-type pokémon seem to be a lot less common in that area. (I chose a random example, I'm not sure it happens in that alleyway and can't pinpoint a specific occasion where it happens, which brings me to the point of making this topic)
It could be that, or it could be just observer bias, so I figured I'd better ask just to make sure.