Hi Brad,
What type of material are you cutting? Is it a large design, or a thick material? There are two possibilities, from what I know:
1: the cutting mat is shifting while you’re cutting, often referred to as “skewing”.
2: you’re experiencing mechanical slip, which can look like skewing.
Regardless of which, I recommend the following:
Make sure you don’t have too much blade exposed: You just want the blade to barely cut through beyond the thickness of whatever you are cutting. You want the blade to merely “kiss” the cutting mat.
Slow the cutter down: If you’re cutting a little too fast for the thickness of material you’re cutting, you can cause extra resistance.
Try a new blade: If your blade is dull, this can also create resistance, in turn causing the machine to skew.
Hope this helps!