This meshes have 2 custom LODs. I think this happens in the transition from 0 to 1. For some reason LOD1 shows this problems.
I’m using lumen, have a directional light, skylight, skyatmosphere, exponential height fog. All are movable.
I have tried tweaking with the setting of all of this but nothing.
Okay, it is LOD1 that causes this problems. To import it I went into the static mesh editor, then selected custom LODs, then in LOD import I simply selected Import LOD Level 1.