Funny thing is that I have a third 1-pounder tin, around the same batch date, but it is not bulging (yet). And several 8oz'er mini-tanks that are also looking happy.
The bulge is barely noticable, the base has pushed out but not past the height of the lip (so the tin doesn't wobble). And the top has a very noticable convex bulge, that seam is probably going to yield first.
Ordinarily I would ignore the bulging (except for checking on their seals periodically) - but since the same blend and around the same timeframe did have mold problems, I'm a little concerned. And I don't have enough jars to store 2 lbs into, so thats problem #B. I suppose I could always trade what I can't store or smoke up - assuming its not rotten