When a mesh in Blender is Duplicated and exported as an FBX, then imported into Unreal with Combine Meshes unchecked, then both meshes reimported, one of the meshes has another mesh added to it. The mesh looks as though it has been imported with the option Combine meshes enabled.
Expected: No other meshes are imported or combined. There is still only one cube
Results: Another mesh is imported and they are combined. There are now 2 cubes
There's no existing public thread on this issue, so head over toAnswerHub just mention UE-56485 in the post.