TSSphereCollider rotates randomly when it shouldn't

Got an issue with a simple TSSphereCollider. After falls onto the ground it begins to roll randomly in a direction.
There are no external forces except default gravity of 0,-10,0.

Why is this happening? The Sphere should be simply colliding with the floor, not rolling away!
One thing I noticed is if I put the sphere at the world origin but with some height to let it fall down, it behaves as expected with NO rotation happening after the collision.

How can I fix that?