moving two rigidbodies with movePosition() doesn't trigger their colliders

There are objects A, B and C. B is the child of A, C is free. All of the objects have rigidbodies, however, A doesn’t have a collider - its collider is object B. A has a script attached which fires when when its colliders are intersected. All colliders are triggers. Now, C is being moved around using movePosition(). B moves symmetrically to y axis and follows movements of C. Yet the trigger messages do not fire off. What could be the cause?

Edit: It appears that the rigidbodies are the answer. However, I would very much like to still have them attached to the objects.

This is what happens when you try to ask fairly abstract questions after midnight and suddenly forget your vocabulary. In any way, the answer was to use movePosition on object C in FixedUpdate() and transform on rigidbodyless B in Update(). That way there is no stuttering while moving the objects and all works just as planned.