Shifted Design When Cutting

[NitroRustlerDriver 1]

I've got an MH871 running Flexi 8.1. Started have a strange problem I can't seem to fix. The plotter seems to loose steps or something as it is cutting, so the design gets shifted and stretched in one direction (with the rollers). It doesn't do it everywhere, only in some spots and always in the same spots (if I cut the same design more then once). It does it on several different designs and files. What is going on here?

Here is a picture showing what is happening:

Note that the tips of the forks are angled and the middle section of the fork is not aligned straight across. The knife came out fine, but you can also see the corners of the box on the right side is wavy and not right, yet the left side is fine.

Does this with both a knife and a pen, in vinyl or on paper. I've checked all my settings, nothing has changed. Unplugged the machine and restarted it, restarted the computer. Nothing seems to change anything. All of this just started happening suddenly for no reason.

[MZ SKEETER 4,709]

make sure your belts are all tight...