I’m hoping that perhaps someone has encountered this before and can offer a solution.
The light is cast from one direct light pointing in the same direction
the view-port in attached screen shot is facing.
As you can see there are shadows there that shouldn’t be. 
Using unity indie/free w/dual light-maps, haven’t tried single light-maps,
but I don’t really see how that should be a problem,
unless dual light-maps aren’t supposed to work in the free version?
You merged all the rocks together with the combine children script? If so, the all share one texture as it is one object after the combine. That can create this problem.
Or, you could have uv’s that overlap. Try the lightmap uv’s checker in the mesh import window.
Dumb question: did you recalculate the lighting after you composed that scenery?
Nope, I dropped them all under an empty gameobject manually, no script involved,
I did use a script to break the prefab status on all of them later on though. 
You know, that helped!
I thought the secondary UV’s for lightmap would be generated by default, silly, silly me, thanks. 
Also thanks megamaltese for asking, but I’m not sure what you mean,
in unreal there’s a way to quickly recalculate lighting faster with the assets data already in ram for the second time around, but I haven’t located anything like that in unity, only the same bake buttons…?
