I had a new set of tires installed in early August. I went back yesterday to have the tires rebalanced and targeted on the rims for a road force issue. After Discount Tire remounted the tires I noticed the pressures were off so I stopped by Costco on the way home. I removed the caps and one of them came off without turning it. I adjusted the tire pressures and started reinstalling the caps. Two of the caps were too big and did not engage the threads on the front tires. I looked a little closer and noticed that the valve stems on the front tires were a different design than the valve stems on the back tires. Three of the four caps were for the longer stems on the two back tires which surprised me. I thought the valve stems were part of the TPMS rebuild kit.

My questions:
Is it possible that the TPMS sensors are incorrect in two of the tires or are the valve stems independent of the TPMS rebuild kit?

The TPMS monitoring system seems to be working fine. The Costco technician stated that I have two different TPMS sensors installed.