Containers and Families don't mix reference associated instances.
Lets say you have 2 objects and 2 families
If hitbox overlaps Attack
destroy movebox
This works as intended with Containers and instancing.
if hitbox.family overlaps attack
destroy hitbox.family
This works as intended, destroying only that one instance.
if hitbox.family overlaps attack
destroy movebox.family
This destroys every movebox.family instance. It should hopefully recognize the associated instances of the family objects.