Colliders added ahead of time, and at runtime cause spinning

The hierarchy of my object is RigidBody at the top, mass is 1000 then child game objects underneath this. One child has a couple of box colliders. Another child has a bunch of scripts which at start create prefabs and attach them. These prefabs have box colliders as well.

If only 1 of these 2 is enabled, everything is fine. If both pre-created box colliders and runtime created colliders exist, the object spins out of control instantly on start of the app(even if no forces are applied). I tried resetting the center of gravity in update and when the runtime colliders are added back to 0,0,0 but that did not help at all.

Does anyone know why this is behaving this way?

Solved! A sneaky extra rigid body was on one of these guys. So when I had only the first group, the root rigidbody was the only thing there, and when I had only the 2nd group, the root rigid body had no colliders so nothing bad happened. And when both were they they collided with each other!