Just came across this bug Unreal Engine Issues and Bug Tracker (UE-32299) after UE4 told me that lightmaps may look incorrect on LOD1 foliage, after building lighting:
Instanced meshes don’t yet support unique static lighting for each LOD, lighting on LOD1+ may be incorrect
I have foliage in my project that uses the same lightmap UVs for LOD0 and LOD1, and the language in that editor message and in the bug report imply that LOD1 meshes will just use the LOD0 lightmaps, which would be perfect for me, but it seems like no lighting at all has been built for LOD1, and the meshes are black.
Is the wording “may be incorrect” just a formality, and it’s actually impossible to have statically lit LOD1 meshes? Lightmap settings for LOD0 and LOD1 meshes are set up in the exact same way in my project, and the lightmap UVs cover the exact same space.