Hello Peter,

i read quite all the 97 result and i found 3 things that could represent the problem:

- Number of substeps;

- mesh size;

- Normal stiffness factor.

About the mesh size, i'm limited by student version so i can't refine below a certain size. 

I tried to increase the number of substeps from 2 to 8 and change normal stiffness factor to 0.2. I checked constrains and geometry too but the problem still occurs.

What else could be wrong?

Below, my last model

Thank you