I am looking through the areas on the xmas maps to find what is worth searching for, when, and if I can catch multiple things with 1 sync. One of the most important things about this is looking for times when common pokemon I do not want (rattata, poliwag, magikarp) do not spawn. Now Snowfall Valley surfing finds me magikarp, which I would like to avoid. However in the pokedex, it does not show up as a place Magikarps appear(checked it like 20 times, had other people check it too).

 

The bug is magikarp not showing up in Snowfall Valley in my Pokedex.

Same with me

The pokedex only has a limited amount of space for listing where Pokemon can be found. Since Magikarp is so common there are simply far too many places to all fit in the listing. Zubat is the same. If you look there you will see that zubat is missing all of its earliest spawns since they get bumped by more recent spawns. I haven't checked at length but things like Rattata and PIdgey I would also assume are the same.

Oh! Ty