Anima2D - Deform and stretched sprite mesh when rotating with bone

Good morning I'm trying to get some animations with Anima2D with bones and sprite mesh.

My problem is that when I rotate a specific mesh that represents a wrist it is stretched and deformed.

I attach images to better make understand my problem.

This is when wrist mesh is not rotated

And following is rotated mesh, as you can see it's deformed:

And also in image at following link wrist is shorten: Image of shortened wrist

It seems child bone is shortened and stretched when rotating, but I can't figure out why.

Thanks