When I brought my new Impreza home from the store, the tires and TPMS was all fine. I took a long drive and the monitoring system light came up on my dash and I found that my rear right wheel was at around 18 psi, the manual specifies that the rear tires need to be around 32 psi. This reminds me of when my dad picked up his 2016 WRX and he had the same problem. He simply filled the tire with air, and never had the problem again. Hopefully mine is the same way.