Prevent corner cut with diagonals

Sorry for the title but the Website told me to be specific and I always have some problems with making understandable what I mean not having more than one sentence ^^ (I know, thats bad) I'm currently working on my Pathfinding Asset (this one) but what I have different here is that I don't use a navmesh, my Pathfinder "sees" it's environment without calculating it before. Therefore I create knots and check if something is in between of them

Works perfectly. But now I'm creating ramps where I only tell my knots what their distance to the ground should be

(Imagine for the picture that the elevation can be anything, |K1K2| = |K2K3|, |GroundK1| = |GroundK2| = |GroundK3|) Yes, I can solve it by a layermask but I don't want to do that because I don't want to tell the user to put every ground gameobject into another layer. I myself found a few complex possibilities how I could avoid this problem but I don't like them because they seem "unstable" to me. If you have an idea what I could do, from that you think that it is an efficient way of doing it, please tell me.