I opened up another pkg. of blades and tried both of them with NO problems. I made sure the first pkg. I opened I only had ONE blade in(yes, I've tried to put two in at a time,duh!!) and I've tried these other blades on different cutting boards(I have five besides the rotating mats) and it wasn't the mats problem. I've set these blades aside in case I run into more with the same problem and then I'll take them back to the store for a refund or exchange. With the price of gas and having to drive 25 miles to my HF I can't justify returning a couple of blades at a time especially with the FANTASTIC price that I paid for them(I was lucky enough to get ALL of mine for 2/$1.49)!!! I'm happy with the one that's in my cutter now and will keep track of how long it lasts.