The problem is really if speed of ball gets to small. On higher speed it bounce perfectly and it never calls OnCollisionStay handler, but I want it to also bounce at small speed.
I am using Bouncy Physic Material for ball with Friction Combine at Minimum and Bounce Combine at maximum. Rigid Body with drag 0 and Angular Drag 0, but i have a feeling i have to resolve this in code.
Any advice?
So what is the problem exactly? It is calling OnCollisionStay and you don’t want it to?
Yes, I would like to avoid OnCollisionStay if possible. I want it to bounce after OnCollisionEnter like it does with higher ball speed. It goes right into OnCollisionExit.
Why do you want it to skip over OnCollisionStay?
Because after OnCollisionStay it never comes to OnCollisionExit, it stay stuck in OnCollisionStay. What i need is for my ball is to bounce continuously.
I think i am on good track to solve this by caching velocity.normalized in OnCollisionEnter and getting velocity.normailized in OnCollisionStay. after comparing them i can see witch coordinate is getting smaller. Then I’ll take coordinate values from cached OnCollisionEnter and change direction to the one that is getting smaller. I’ll have normalized vector with right direction. Then i just need to add speed to it and fire it away from damn OnColliderStay handler 
nah, that is just another failure 