I removed the Solid behavior for the house.
I added a different solid sprite and placed it invisibly on the map.
I created the following event and action in case the calculations were wrong:
On start of layout / regerenate pathfinding obstacle map
I rechecked all the collision points in all the sprite's animations (all the same).
I moved the sprite's focal point to the center for all the animations.
I rechecked all the events and actions.
Still the problem persists.
So I added:
Sprite / On Pathfinding failed to find path / sprite move forward 30 pixels.
Of course it's ridiculous but at least it pops out when it gets stuck.
It works but it doesn't look right.
I'm not happy about this at all.