I've started getting a constant "Key battery needs replacing" message on the center cluster, along with the alert at the top of the MCU. This is in a 2017 S100D. This came AFTER I changed the battery on the fob. The battery is known good (brand new out of the box). I've rebooted both the MCU and center instrument cluster, and then also did a complete power-down, but am still getting the message. I also changed the battery in the spare FOB and the car shows the "needs replacing" message with the spare fob. Both fobs function properly. I'm fresh out of ideas. Any suggestions would be welcomed.