It was the same reed?? Strange. The reeds that I got that had a crack, it was kinda hard to see the crack, and it didn't go out to the edges, but it would have if I ran them. It was a little curved crack in the center of the top reed (they were the dual stage power reeds).
Have you checked out the top end to see how the piston is?? Maybe something kicking around in the crank is making contact with the reed?? Which reed is it?? top or bottom, left or right?