Spawning Physics Actors is making my AI character and Player Character Fall through the ground

The title says it all.
I brought a small static mesh and attached a blueprint to it which spawns small physics objects. ( lets call it TREE )
Those physics objects work fine I double tested them.
But as I bring the new TREE into the map, the AI character and the Character fall through the ground.
As I remove the TREE from the map, they work fine.

I’m using this particular node which is Set Angular Velocity to Static Mesh ( which is a physics object ) Only in that case the characters are falling through the floor.

Is there a workaround ? I just want the physics spawned actors to be in different orientation when they fall.