I was alerted to this problem after seeing someone else's thread in this forum that showed a video of the exact same leak. The first day it rained after I bought the truck, I decided to check to see if mine leaked. After pulling out the rubber mats, the carpet seemed slightly damp on the driver's side, so I pulled the trim and carpet up, and the back of the carpet was wet. Not soaking wet. The floorboard had some drops of water in many of the depressions going all the way towards the center console, but in no way were they full of water.
The push pins that hold the carpet came out much easier on the driver's side than the passengers side. Maybe the dealer found and dried the carpet before delivery? If so, they must have moved fast because I picked it up the day it was delivered. (I did notice when I picked it up, it was driven to the front, and the salesman went out and then the truck left and the salesman came back. He said they were going to fill it with gas, but it took a looong time for that to happen) And it sat for a month at the factory lot before getting shipped to the dealer, so it might have gotten soaked there.
I stuck my hand under the passenger side carpet, and it felt dry. I didn't do the water test on the passenger side. But now that you asked, I will pull the weather strip and see how the pinch weld looks in comparison to the driver's side.
Cheers
Gerry