I had some issues with trigger events recently because I completely forgot that one dynamic or kinematic physics body was required. I'm coding my own kinematic controller for the moment, so I wasn't in need of the physics simulation. Took me a bit to figure out, and I do seem to recall seeing it in documentation somewhere. But I'm curious as to the purpose of this. Why is a non-static physics body required? It would seem like checking for collider overlaps would be sufficient without a physics body. Its been a while, but I seem to recall a similar requirement for gameobject colliders and ridged bodies.