Opened up a new box of Ball flats and noticed that they had a weird little bump on the edge. At first I thought it was just something new... Kept looking and realized that only four of the twelve had it. They might be fine but it's too much work to can stuff to risk it not sealing because of a faulty flat. I'm going to stick one of them in an envelope and send it to the folks at Ball and see if they will replace.