Are you referring to the red triangle on the tach/speedo? We've had it, too. It's off as fast as it came on. Nobody in front of us for miles, both directions, when it happens. When I had my '15 Silverado, it would do it when the sun was shining right into my eyes, or when I was "chasing" someone through the serpentines, going on/off Edwards AFB, even if they were in the other lane. (The lead/other car would come across my nose, in their lane, and because their vehicle was within "X" of the nose of my truck, the collision avoidance would "fire off.") If I'm remembering correctly, the sun was setting when our GLC300 collision avoidance would trip.I have also had Collision Prevention false alarms.
Most of the time it's just the 2 beeps but I have also had the car brake for no reason from time to time with no obstruction.