Hey @Norgutg,
thanks for forwarding this issue, I am already aware of this problem and unfortunately it is an overall error of the tile itself and not the map.
It will be fixed with the next client update
while this may seem like a bug, it actually is not a bug. Unfortunately it is not possible for us to have spawn colliders on edges like shown on your provided screenshot.
That is because of the given restrictions we have in the Mapping Editor, so to summarize the situation, whenever there is an edge south of an area which players can access you wont be able to encounter pokemon.
We try to avoid these cases as much as possible but it is not always possible with the way we are creating maps.
I hope I was able to clear your doubts and explain the situation to you in an understanding way.
Clumsyclef's post in Diglett Cave on Route 11 issue was marked as the answer