Lightmass and upgrades

Something seems weird between updates and Lightmass. I started a new scene in 4.1 because in 4.02 when building lightmass shadows would become very dark and inaccurate… This morning I updated to 4.1.1 and the exact same thing has started happening. Why is this?

I played around with LM resolution, changed the bounce properties and it doesn’t make a difference. I’ll probably have to start the project again!.

Examples below:

Oh sorry for the late reply, we all run Nvidia GTX 780’s with 3GB of ram. I think 5 of the machines have Titans in them…