I think it's an optical illusion. Everything in the picture is leaning to the right, the trees, even the cracks in the mountain. Meanwhile, there are horizontal lines on the front of the tower that you expect to be perfectly level from that vantage point, but they are actually sloping down. My hunch is they actually are not parallel to the ground on that face.
If you obscure that face, the effect vanishes.
The reason you can't fix it is because the strong vertical lines on the church are spot on 90 degrees, so any budging makes them look off.
At least, that's my take on what's happening.