Landscape splines dont work with linetrace?

Good evening dear community,

I struggle with the problem to detect Landscape Splines via linetraces.

My intention is to place objects everywhere but on the landscape spline itself. However, sending a linetrace to the location on the landscape where I want to spawn the object, it only hits the Landscape itself (LandscapeHeightfieldCollisionComponent) and not the LandscapeMeshComponen from my landscape spline.

BUG?
Somehow it worked for once, when I accidentally activated “vertex painting” for the Landscape Splines (a light purple triangle grid was shown). Since I cannot get this grid to appear again, my question ist how can I detect hits with linetracing on a landscape spline, and please don’t tell me that this is not possible at all.

Thank you.