I have the new version pockets with taped seams and (supposedly waterproof) zipper. I think it might be the placement of the zipper across the top of the pocket, so that falling rain hits directly on the zipper. If the zipper were high up on the front of the pocket (like on the Zimmerbuilt pockets) then the zipper wouldn't be getting as much of a "direct hit" with the force of the rain and, I'm guessing, would hold out the water better.
My belt pockets weren't sloshing around, but definitely some wetness inside. Camera in a ziploc survived just fine.
