lidar isn’t able to read the state of traffic lights as far as I know, and I believe lidar based systems detect the location of traffic lights from maps
Yeah. But that's not what the OG comment is suggesting. The use of Lidar here would rule out a light resembling a traffic signal by virtue of there being no laser reflection of that object: lidar would complement vision to rule out false positives.
They look different so it should be able to tell them apart if the model has been trained on these shapes. My robot vacuum uses lidar, the maps it makes of my apartment when it cleans are remarkably accurate where you can identify certain objects pretty clearly.
If you overlay the point cloud with the image you're interpreting, it should become apparent that the "yellow light" has no accompanying red or green lamps, no pole holding it, no shroud around it, and is at some distance exceeding the depth limits of your lidar.