While at the airport KBDU (03.27.25 @ 2215Z) I calibrated the barometer using DEM resulting in the correct altitude 5285. I then set barometric pressure to the airport METAR 29.86. The D2 Mach I is connected via Bluetooth. Within a few minutes the pressure changes to 29.96 and the altitude is 5378. This happens every time with similar spreads.
Thanks Dan