"Extra" collider in converted entity

I have an object I am converting to an entity:

1. GameObject - Physics Body
   1. PhysicsShapes
      1. Colliders

I am using CastCollider and it keeps colliding with the root object, which I have not added either a physics shape or a traditional GameObject collider to. In the entity inspector, that object has a Physics Collider component on it, which I did not add. The hit object from the cast is the entity from the root object (1), not one of the constituent colliders/shapes (1.1.1), which should never be able to collide with my CastCollider in any case, due to geometry. I have no idea what "shape" the offending collider has. Nothing shows up in physics debugging view showing the hit.

Is that expected behavior? Is there any way to control it or prevent the collision?