Material slots switched (not in level, but in material editor or exported fbx)

Hey. I’m currently using a content pack i bought with some great assets.

Some of the multi material meshes behave really odd though.

This is one of the problematic pieces in the level.

Non_edit

But in the modeling mode using “edit materials” the 2 materials switch. looking like this:

Same if i export the static mesh to fbx, or use “create static mesh from actor” to group a bunch of them.

Only way i got this working is to

  1. Remove all LOD
  2. Separate the mesh by material
  3. Delete the material slots
  4. Create new material slots
  5. Use “Merge actors” to create a new object (union or boolean/union) will lose material slots.

Any clue on what’s going on? As it is a content pack from the marketplace i don’t have access to the source files.