Equivalent Nodes with Filter for Unbound Dimensions

I have an Unbound dimension created where I have two hierarchy and node sets sharing a node type. I am able to select the related viewpoint for the primary viewpoint and enable the Equivalent Nodes with Filter validation. However, when I add a new node, the dimension validation does not trigger, and I am not able to use it as a Selected Validation for a viewpoint validation either.

Is this expected behavior with Unbound dimensions? As far as I can tell, the EDM documentation suggests the only requirement is sharing the same node type, which I am doing. Please advise - thanks!