GPU Lightmass in 5.1 - can't delete LightMaps

Not sure if perhaps a bug but in a very simple scene after building my lightmaps using GPU LightMass in UE 5.1 I am unable to delete them.
ie Force no precomputed lighting is enabled and I complete an additional buiuld.
Have done several times and even relaunched my project. Lightmaps are still there!
I believe the lightmap data is actually embedded in the level asset so cannot simply delete from the desktop.

Well this is more strange, I can’t even bake my scene with GPU lightmass in UE5.03 this is what it baked all white blob meshes. I have tried almost all perfect settings for GPU to work but its still not baking anything.