HLOD StaticMesh shows black on Vulkan (it seams Lightmap issue)

Hi there, hope you guys can help me. Im creating ArchViz on OculusQuest using the LOD and additionally the HLOD System. In the Editor Preview with SM5 it looks good, but under he Vulkan preview the merged StaticMesh is black. It looks like, there is an lighmap issue. When i build the lighting again, the merged HLOD Sm looks fine again, but the original SM Meshes have destroyed lighmap Information.

Also under the HLOD Coloration in SM5 it looks fine (blue). Under Vulkan its black. So it could be its not an Lightmap issue, maybe the merged SM itself cant be displayed under Vulkan (although the black shape of the merged SM is visible)

Any ideas? Thanks and greetings,

tested under 4.23 and 4.22: same issues.

I’m experiencing the same error on 4.26.1