Why LandscapeLayerWeight works but LandscapeLayerBlend does not?

I try to follow the grass tutorial in UE5 docs (https://docs.unrealengine.com/5.0/en-US/grass-quick-start-in-unreal-engine/). It is another page that has not been updated to UE5 so I assume it should apply to UE5 as well.

Everything is fine until I try to do blending of Grass and Rock textures. The tut suggests to use LandscapeLayerBlend and I do exactly as the tut says but the preview is always black (actually looks semi-specular blue). I have preview weight set to 1.0 for both layers.
If I use LandscapeLayerWeight, it works.

Can someone explain why this happens and how to fix it?

Thank you!

Hi! Have you found an answer to this?