Physics Collisions - objects overlap and collision is delayed, why?

hopefully you can see in the attached picture that I have 2 physics objects a ball and a platform.  

The issue is that when the objects collide on the right rounded-corner of the platform the ball overlaps the image and it looks bad before the collision event occurs and the ball bounces off the platform - why does this happen and what can be done about it?

It doesn’t happen on the left side?  The ball is set as a bullet to increase the collision detection but that doesn’t change the effect?  Both objects are set as dynamic.  Any ideas would be helpful.

Thanks!