Deleted objects still calculated and casting a shadow in Lightmass (Datasmith issue?)

Hey everyone, mystery time!

Our team recently completed a project in UE4.20.3 and we are having a strange issue. We have placeholder, long since deleted objects still showing up in our light bakes. These were very early placeholders brought into the scene with Datasmith and have been removed when the final furniture was modeled. We have tried every possible thing we can think of to verify they aren’t in the scene anymore, yet their ghost still haunts us.

Please see the attached pictures for more information. We have tried the following steps to find or delete these ghost objects (nothing has worked):

  • Verify they have been deleted in Max and re-export Datasmith and Sync Actors
  • Manually delete the actual datasmith .uasset files in the Content Browser
  • Manually search the World Outliner and attempt to find these objects
  • Manually search all levels to confirm they aren’t on some other level
  • Clean and Validate Lightmass Cache
  • Delete and rebuild Derived Data Cache
  • Build Geometry on all levels before building Lighting
  • Add object back into Datasmith but move them 500’ down under the floor, these ghost objects still bake in their same position
  • Add object back into Datasmith but set to ‘Movable’, uncheck ‘visible’, check actor ‘hidden in game’, uncheck ‘cast shadow’ so they can’t be calculated in Lightmass

So we can’t seem to figure out where these are coming from. Is there some viewmode we could use to catch a glimpse of them, or some other setting that might be preserving old meshes in Lightmass?