In the discussion, the cop says there was another 40 sign back up the road. The one they passed on the video looked like a temporary construction sign. Don’t know what the other one might have been, or even if it was there.
I've had more than my share of tickets (most many years ago when I was younger and drove faster). I deserved almost all of them. A couple or three times I absolutely didn't deserve the ticket. But I always signed them. And I went to traffic court a couple of times when I was right... but the average citizen stands no chance in traffic court.