Incorrect preview of light on meshes

So, I’ve built some meshes in Maya and generated a UV Lightmap when importing into UE4, its layout is pretty simple and looks perfect after lightmap generation.

But After I build my static lights some parts of the mesh display Pitch black, but when using Detail Lightning, the lightning built looks like it is correct. Take a look at the screenshots:

Detail Light view:

Default lit view:

Is this an incorrect lightmap generation issue? Shouldn’t any errors on lightmap/light build been seen using detail light view?

This has effect on several meshes that I’ve created, I’m trying to build the light using only 1 spotlight and nothing else.