When there's a heavy drag, tracking gets to be more tricky.
If i have to do layers - like reflective on vinyl because I want to be able to peel it the reflective off easily, I always do multiple passes - the force is lighter so there's less drag on the material when it's moving, less chance for the tracking to go askew.
And do you have rollers on the part that's being cut, as well as the 'outside material' because once there is definitive cut through your material, only the part that being pinched by roller will want to jog back and forth, there by adding to drag. If you were trying to do with paper, the paper would bunch. That's why machines like the Cricut need to have 'carrier' sheets that have a light adhesive - it keeps everything moving as a single piece, even though it's cut so stuff doesn't bunch or get caught.
You're basically cutting something that's 12x thicker than 651 vinyl, which is done in a single pass. I wouldn't even attempt to do a 30mil anything in a single pass.