I have a 2-month-old 2021 Ranger Lariat that when the Air Conditioner is on a low flow of hot air (like if the heat was on) comes out on the floorboard area of the Passenger seat by where the left leg would be. My wife noticed it yesterday when she had flips on. She hasn't noticed it before...
I know you found a harness issue so this might be a moot point. I had the same issue at 900 miles on my Ranger (it now has 1500 miles) Started it, drove it, no issues, the next morning wham, lights flashing all over the place, no audio on the radio but the main difference was when I started it...