There are a lot of threads handling ladders, this is specifcally about the ladders leading to the roof on appartement buildings from the top floor. These are the appartement buildings without an elevator shaft.

When you climb up the ladder to access the roof you fall down again once you reach the top. I believe the reason for this is that once you "get off" the ladder, the game places you directly on top of the hole, causing your character to drop. I have experienced this at every appartement building of this type.

Possible fix would be to move the "get off" position. {F29660} {F29661}