The factory door jam sticker states that the loaded tires on the vehicle should be at 30 psi, and the unloaded spare be at 50 psi.

The rating on the sidewall of the tire is for the unloaded pressure.

Since the Bridgestone A/T Duelers, are rated at 50 psi, this is correct for the spare. Once the tire is placed on a vehicle the tire is under a load and the psi changes.
I usually keep my loaded tires set at 37psi, so there is no issue when the temp. drops.
My sensor went off once, since I bought the truck, and the PSI was at 32. Increased to 37, and no issues.
HTH