There are FBXs exported from 3dsmax with 2 UV channels
Then import them into UE4.13
In FBX Importer Dialog unselect the option “Generate Lightmap UVs”
Editing the StaticMesh you can see there are 2 UV channels, and “Light Map Coordinate Index = 0” . The correct should be “1”
If i select the option “Generate Lightmap UVs” in FBX importer dialog, these staticmeshes would have 3 UV channels and “Generate Lightmap UVs” would be set to “2”