Trying to delete Splines facing away from a Normal direction which mostly works fine but not when using a Vertex Group / Weight Paint. I’ve tried separating the Geometry and just doesn’t want to work.
I’m guessing that the Sample Nearest node, even after splitting the geometry, finds a point in the split geometry that produces this result. I suggest not using geometry separation, but additionally finding the weight attribute in the group and subtracting it from its value using normals. An example of an alternative split by reference.