BEPUphysics

Yeah, actually it was problem and I am glad I helped to discover it, although my initial suggestion was wrong.
Thanks Norbo

Hello Norbo,
It was my bug after all, while playing with settings for my demo I had set default bounciness of the cubes to .3f, that was the cause of the problem...
Thanks again and sorry for wasting your time.

I just sent you a PM with source code of my project and some additional info.

Hi Norbo, and many thanks for your assistance.
I am testing it using Unity for visualization, so I compiled the dlls for .NET 3.5 and without compilation symbols(WINDOWS;ALLOWUNSAFE)
This must be the reason for the problem...

I am doing some tests with the engine, and it works great, however I noticed a bit strange behavior in situations when you have a stack of objects. I am attaching screenshots of a small piramid of cubes, base is 10x10, total 380 cubes. I leave a small space (.05) between the horizontally placed cube...