Are you sure that it's a nick in the blade? If you cut over a damaged part of a mat, the blade will skip. Try flipping the mat. If it's still an issue, did you get all the blades from the same pack? maybe you got a bad batch. The only other thing I can think of is that the blade is somehow hitting the side of the cutter, but can't figure out how that would actually nick the blade as they are all plastic.