21 Yukon XL carpets soaked under OEM weather mats

[BDenali21]

I’ve read about a lot of Chevy owners having this issue but haven’t been able to find any GMC owners with the same problem. Carpets under OEM all weather mats were soaked. Some places had mold growing on top of the carpets. Dropped the car off 2 weeks ago, new carpets were ordered within 2 days of the car being dropped. Dealership is saying that the back hatch seal is bad but the back ‘trunk’ area was the only floor board area in the entire car that wasn’t wet. The car is also parked at an incline a majority of the time with the rear end being at a lower elevation. Due to the above the diagnostic isn’t making much sense. Car is under bumper to bumper warranty so it’s being fixed but GMC can’t seem to get the replacement carpet to the dealership. It seems a lot of the parts on these cars are hard to obtain. We had an issue with the motorized sliding center console and it took over a year to get the parts to fix it. I’m a little concerned that a part(carpet) you would think would be readily available isn’t available or being shipped. Has anyone else had this problem? If so what was the issue, were the carpets replaced and how long did it take to get the replacement carpet?