I would think that you are spot-on about the change in their behavior, because all dogs, especially basenjis,have a great sense of smell and know about the local "darling"….
I have two basenji girls that got along fabulously, but suddenly started to snark at each other. It quickly escalated to nasty fighting. When this happened, I asserted myself as the dominant female- separated both of them, told them NO! They both calmed down. As soon as I possible, I would take them for a RUN, with me being the leader. At the beginning of the runs, the smaller one would try to nip at the other one's neck, but I'd pull her leash and run faster. The two girls settled into a running pattern and I used my voice to reaffirm the good behavior. I'd also stop along the route with milk bones, tell them "TREATS", and to give them both a chance to socialize and eat along the way. It seemed to work, because after 2 days of snarking, they returned to being better in the house.
Stay patient.