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.

Try using raycasting first, from one point to the other. If it returns anything else, then it’s blocked.