When importing a LOD model, LOD material can get added as element 0, not preserving previous material assignment.
It's not possible to re-order/delete the automatically added Element 0 WorldGridMaterial.
1. Import SM_pPipe.fbx with materials
2. Place two SM_pPipe models in the level
3. Assign a different material to one of the model
4. Open SM_pPipe and add SM_pPipe.fbx as LOD1 of the above static mesh
5. WorldGridMaterial gets added as Element 0. The material assigned to LOD0 in step3 is now applied to LOD1, not LOD0.
Expected result: Importing a LOD would add materials after existing elements. Previous material assignment to a LOD level would be preserved.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-51135 in the post.