It has been my experience if you have a cutting tool walking and you are not applying excessive pressure, you have one side of the cutting edge dulled more than the other side. You might inspect each tooth to see if that is the case (if it has teeth) or if the cutting material is worn more on one side or the other. My replacement cutting tool bills would have been much less over the years had I been a faster learner in letting the cutting surface do the work and not adding more pressure to speed up the job and taking the time to carefully inspect the cutting surfaces when a tool was not cutting normally. I was a slow learner in properly sharpening tools as well, but it sure pays off now. I am struggling with teaching my son how to properly use and treat tools, but he is coming around because he has to buy the replacement tools that he breaks or destroys.