I've had one leak as well... A old style with a tire tube
I should have realized that there was a reason why I was slowly settling further into the water.... but that was it. It happened very slowly.
It wasn't until I "beached" and tried to pick the thing up that I realized it had gained about 40 pounds of water weight
It wasn't a big deal, in fact I was far more concerned about the huge snapping turtle that was following me around