4.20 fbx import - generate lightmap uvs doesn't update the lightmap coordinate index

Up to 4.19, when importing an fbx file and using ‘generate lightmap uvs’, the light map coordinate index would be updated (changed to 1 if only 1 channel was present in the original fbx). In 4.20, the lightmap coordinate index isn’t updated (still 0) resulting in black objects after building lighting.

Easy to replicatie;

  1. import an fbx (an object with a material + texture), use ‘generate lightmap coordinates’
  2. edit the imported StaticMesh
  3. under ‘general settings, the lightmap coordinate index’ will still be 0

Same thing happened to me in 4.20. Cant believe epic didn’t saw this. Maybe they have fixed this in the hotfix update. BTW I am going back to 4.19. This sucks !!!