OK guys, I too have been dealing with the flipper glass leak.
Mine was leaking so bad that I just said forget cleaning the flipper glass. So I took it in for the leak at one dealership. They replaced the weatherstripping.... with the same part and said that it didn't leak anymore. Two days later, heh, it leaked. Didn't even bother them, I said screw it.
.... until I started to have tailgate latch issues. The water rusted out the tailgate latch. It still worked fine but the sensor was reporting that my tailgate was open, which of course turned on the chime and of course all of the interior lamps. Tried another dealership, the one I usually go to, this is what they said:
"30811 PERFORM DIAG TESTS AND FIND THAT REAR HATCH LATCH IS WATER SOAKED AND AJAR SWITCH IS RUSTED. REPLACE REAR HATCH LATCH ASSEMBLE CLEAN CONNECTOR END AND APPLY GREASE ALSO REPLACE FLIPPER GLASS TO HATCH SEAL DOES NOT MATCH UP IN CENTER CAUSING WATER TO LEAK DOWN TO LKATCH ASSEMBLE CHK OPERATION AFTER REPAIR OK AT THIS TIME TECH.1634"
I got the TSB done, brand new revised seal (which is NOT like the one wingnuts posted, the sealing area is now "ribbed", and I got the little water trough....
It doesn't leak anymore.

I tested it at the coin wash. It is also harder to close now which is a good thing. I always wondered why it was much easier to close the KK flipper glass in comparison with the KJ's flipper glass. Apparently this is why... easier to close allows water in!

To you guys with the leak, don't be surprised if you end up having to replace the tailgate latch in the near future.