Rigidbody collision problem (see screenshot and video)

Hi. I have a target consists of five steel plates of complex shape swinging on the one axis.
Each plate is a Rigidbody with HingeJoint component.
Each plate contains several convex mesh colliders (see screenshot).
You can see the gaps between colliders of the different plates.
But when one plate is moving -- its affects others. In most cases -- the central plate affects bottom plates.
It's impossible but true. Again -- all colliders are convex. Their shapes are clearly visible on the screenshot.
Why it happens and how to fix it ? Thanks

 

Try adjusting the contact offset in the colliders:
https://docs.unity3d.com/ScriptReference/Collider-contactOffset.html

 

Default values were 0.01. Changed to 0 for all colliders. Didn't help a much.