I think I have seen this as well. Radar is an imperfect technology. There are many types conditions that cause the radar to produce anomalies that the software cannot properly interpret. The manual for the 2018 Honda Accord lists several conditions that limit the sensing system's performance (p.512).
- Driving in bad weather (rain, fog, snow, etc.).
- Sudden changes between light and dark, such as an entrance or exit
- There is little contrast between objects and the background.
- Driving into low sunlight (e.g., at dawn or dusk).
- Strong light is reflected onto the roadway.
- Driving in the shadows of trees, buildings, etc.
- Roadway objects or structures are misinterpreted as vehicles and pedestrians
- Reflections on the interior of the windshield.
- Driving at night or in a dark condition such as a tunnel.
- Driving on a snowy or wet roadway (obscured lane marking, vehicle reflected lights, road spray, high contrast).
- Driving on curvy, winding, or undulating roads.
- The road is hilly or the vehicle is approaching the crest of a hill.
Good to know that others have seen it. I have also seen reports on the web. I did notice on p.513 - applicable conditions when there is no vehicle. Oh and it's "CMBS" not "CMBA"- my bad.
p 515 on PDF (513 on paper)
The CMBS may activate even when you are aware of a vehicle ahead of you, or
when there is no vehicle ahead. Some examples of this are:
■ When Passing
Your vehicle approaches another vehicle ahead of you and you change lanes to pass.
■ At an intersection
Your vehicle approaches or passes another vehicle that is making a left or right turn.
■ On a curve
When driving through curves, your vehicle comes to a point where an oncoming
vehicle is right in front of you.
■ Through a low bridge at high speed
You drive under a low or narrow bridge at high speed.
■ Speed bumps, road work sites, train tracks, roadside objects, etc.
You drive over speed bumps, steel road plates, etc., or your vehicle approaches train
tracks or roadside objects (such as a traffic sign and guard rail) on a curve or, when
parking, stationary vehicles and walls.