mnm, I'd carefully look at it to see if there are any imperfections in the glass. I have one with a small bubble in the side, but I've used it for several batches. The one I was cleaning didn't have anything noticeable before I racked the beer into it, but I may have done something to it while the beer was in it. I was using it as a secondary, and the beer was in it for about three weeks. Who knows? It could have just been a week spot that I never saw. I have no idea whether that one was one of the new ones I bought new, or one of the used ones. I have two 6.5 gal that I bought new, and had three 5 gal I bought used, and two that were new. I'm down to four 5 gal, and not going to be buying any more.
I get this damn cast off tomorrow, but I still have no feeling in my index finger. The middle finger and thumb have numb areas, but they are doing much better. The doc said it could take up to a year for it to heal completely, but I may never regain full feeling. Physical therapy will be a long process.