You are going to have a tracking problem with any value cutter,, That is why I chose a Graphtec.. You have to pre feed your vinyl back and forth to get it feeding correctly. You have to start straight from the git go. And never have your machine pulling your vinyl from the roll while cutting,, Have enough vinyl slack behind the cutter to do the job.
Too many new people start adjusting those pinch rollers, then you have more problems.
Too much blade exposed can throw off the tracking also. Make sure you use the least amount of blade to do the vinyl you are cutting.
Not having the cutter on a stand can throw it off also.
Here is a video that can help. Below.. UScutter used to have a video for this, but I can't find it.