Black spots (from lightmass) on far objects

222719-clear.png

near

222720-far.png

far

I found black stains on static objects appear as camera goes far.

Static objects are overlapped.
Near rendering has no problem.

I guess they are from lightmass inside neighbor’s object caused by LOD.

Is there any general solution to this?

I’m considering to modify engine code and shader so that far object doesn’t rendering lightmass.
I’m not sure this would be good way to solve this.