First post on here,
At our shop we have found with the 3M 3200 EGP, 3930 HIP, and 4000 DP that if you cut through the backing side you may have more success. Plotter blade and down pressure is also pretty key. If you have a Tangential cutter that can help you quite a bit as well, but 3M recommends a Flatbed for their prismatic stuff, Hopefully that helps you out a bit.