Static Mesh 's Light Map Coordinate Index set to 4 and execute a light build, the result will be incorrect.

Light Map Resolution is set to a small value (4 or 8), it will build normally.

[Link Removed]

^{1.Download Attachment file.}

^{2.Create New Project.}

^{3.Move ST_Sphere_LMIdx4_01a.uasset included in attached file to project.}

^{4.Set unique UV for Static Mesh's UV Channel 4. (ref 327164-dix4-uv.png)}

^{5.Set the Light Map Coordinate Index to 4.}

^{6.Place static mesh on the level.}

^{7.Start Lighting build/}

^{Result:Overlap warning} 

^{Ref: after Lighting build.png}