HLOD generation failure & Why is HLOD generation affected by the size of runtime grid cells?

(UE 5 HLODs)
I have managed to build HLODs in 2 layers (one is a simplified layer, which is spatially loaded and child of an approximated HLOD layer). Everything is fine, no problems at all.

But then I delete 3 or 4 actors on the scene, generate again, boom, nothing generates. How come HLOD generation suddenly fails so extremely by only deleting 4 actors?

Also, why is HLOD generation affected by the size of the runtime Grid cells in the world settings? If I change that value, I also get different results.

Please, can somebody help?

Hey, did you figure out either of these?