Same problem here and I've come to the conclusion that it's the nature of the beast. The adhesive appears to stick to the blade and pulls the film up. Once this starts it leaves some adhesive residue on the blade exasperating the issue. Every time I try to cut a mask, it's another problem that has to be resolved, what worked yesterday isn't necessarily going to work today.
My only suggestion would be to inspect the blade for even the tiniest hint of adhesive residue to worse, bits of the mask, or try a new blade. The other suggestion would be to reduce the depth of the cut. Do you see evidence that the blade has cut into the backing paper? if so, how much? If it appears distinct, try reducing the depth. It should be faint.
But none of this addresses the issue of the inconsistency of the adhesive, which has been an ongoing frustration and discussed many times. My last batch of 810's adhesive was very aggressive and left residue on the model. Then I tried 810S and its adhesive was so weak it would hardly stick to the model. There's just so many variables that seemingly change for no logical reason, it's enough to drive a man to drink.
Plan B (decals) is a less frustrating alternative. Good luck.