Strange Collisions (...as there should be none!)

Hi everybody,

I'm facing a strange issue and I hope someone can help me figure it out.

When I start my project in playmode OnCollisionEnter is called multiple times, even as there should be no collisions happening. I logged what should've collided, checked it in the scene and made a screenshot for you guys... :) The DefaultContactOffset is set to 0.01 and by looking at the grid I think the distance between this two colliders is more than that. However, when I set it to 0.001 there are no collisions, but I actually want an larger offset to be honest. Any ideas why this is happening?

As you can see from the screenshot I arrange my CompoundColliders as follows: GameObject with Rigidbody --> GameObject as Container for Colliders --> Gameobjects with Colliders

...is there anything wrong with this?

I'm looking forward to some advice! :)

Best regards mat