In the latest update(s) the Contact Sender when set to "Local Only" doesn't sync globally with a Contact Receiver that is using parameter network sync (Two blendtrees driving a float with a transition going back and forth between the two states using the IsLocal parameter in my case). This method worked fine prior and enabled certain types of interactions while using fewer contacts. (Currently I'm only aware of this affecting PC/Quest/Android but it may affect the other platforms too)