OnControllerColliderHit Doesn't always get detected?

Hey guys!

I have been experimenting with the Character Controller and tried using the OnControllerColliderHit function on it. it detects collision just fine, with one single exception..

I have an object in my scene, who moves towards the player when in range. I move it with forces on the rigid body (like i do on 1 other object which collides just fine!). On this object i also have a physics material which is very bouncy (like i do on 1 other object which collides just fine! same object as mentioned earlier). the strange thing is, when the player is not moving, the object just keeps bouncing of the player. When the player starts moving, in any direction, the OnControllerColliderHit gets called.

what am i doing wrong?!