DieHard DIYer

Having issues with smell coming from under counter vented sink drain. Relatively new construction and home built on concrete slab. I installed (diehard DIYer here) the drainage for a doubl;e bowl sink with both sinks connecting to a p trap in the middle. The p trap is connected to the 3 inch main drain via a sanitary T (3 " w reduced to 1 & 1/2 ). Main drain fitted with under sink AAV vent approximately 5 inches above where p trap is connected. Main drain is connected under the slab to the vent stack going up the interior wall and through the roof at a distance of approximately 10 to 12 feet from the sink Most appreciative for any suggestions as to why the smell. Drains operate properly btw Thanks