I ran into the same problem, but my pieces weren't big enough to strip piece so I had to sew each block individually. One side was 12 inches, the other 12 1/4. And I couldn't fix it, but as it is for my bed, I don't care. I sewed them together anyway and let me say, when you have 4 pieces, you can't really tell when they don't match up. You have to look quite close to see them. BUT I'm glad to hear I'm not the only one with this problem!