You could open door to RV and turn on right signal. If you see the door on screen then you are looking at right side with right camera. Easy test. Now you know which side is actually coming on.
I am guessing the CW tech wired tail lights and stop/turn lights on toad at same time brake was installed?? If so, did he use the original light fixtures on toad or did he add extra fixtures for towing?
Is the red LED on dash some equipment that came with brake controller or an idea the tech had?
Your info is correct - the Jensen takes camera trigger directly from turn signal circuit in RV.
I believe you have two options at this point if everything is working OK. You could continue driving just as is or return to CW and see if tech can straighten things out. If he added extra light fixtures, for instance, he could have a screw invading the vehicle harness causing circuit to be confused. If he chopped into toad harness for extra lighting he could have mis-wired something. I can't go much farther without seeing the project - sorry.
2015 Jayco Precept 35UN
Towing JEEP TJ with Roadmaster plates and bar w/Blue Ox Patriot brake
an Aluma low bed trailer with HD Road King and/or Polaris RZR onboard