This appears to be an issue with the TPMS (Tire Pressure Monitoring System).
Recommended Tire Pressure is 36PSI. if you are filling up your tires and the TPMS registers it being 36PSI the horn will honk to let you know that the tire has been filled to recommended capacity.
next, the High range is 40PSI. if you are filling your tires quickly, actually putting air into your tires, when you hit 40PSI, the horn will Honk 2x to let you know to stop filling your tires.
now, for the flashers. if you are sitting in your truck with the Air Conditioning on, you have to assume it's warm outside. Black tires obsorb heat. and this big old beastly engine produces a LOT of heat. as tire pressure increases, but you're not actively filling your tires, then as the pressure hits either 40 or 41 (over the max pressure) the flashers will turn on to make you aware of the pressure building in your tires.
If your truck is like mine, 2021, 1500 5.7L , my front tires always heat up faster than my rear tires. most of the time while i'm sitting still my front tires are almost 2 PSI higher than my rear tires.
you can resolve this issue by letting 1 or 2 PSI out of your tires so they dont approach that 40PSI while sitting.
to turn off, i think you go to settings >> Safety/Driving Assistance >> Tire Fill Assist