I haven't seen that problem on any of mine, but I've only had 3 of them on running engines. I looked at one of mine and it kind of looks like just a paper gasket in there. Did you try tightening the four bolts? If they are tight already, next step could be to take the bolts out and see if the pump comes apart. I did that with one of mine that I have sitting here, but with the bolts out it would not separate at the gasket, and looking down the holes for the four bolts, I can see a bunch of clear silicone sealer in there. If they didn't put the sealer on yours, maybe it will come apart and you can just put your own sealer in there. Otherwise, I would give them a call and ask what to do.
Sorry to hear about this; its the first time I've heard of a problem with those pumps...