Scroll Dial Troiubleshooting DJM S9

Hello,

I purchased my DJM S9 December of 2015.  I quickly got in the habit of using the scroll dials.  About 9 months in, I noticed that it wasn't functioning like it used to.  I'll do my best to explain this.  If i'm scrolling forward in a particular folder of songs, mid-scroll, it will jump back about 10-20 songs.  Note that i'm not going backward at all, this is happening while moving the scroll to the right.  

Since I had warranty on the unit, I sent it back and it was fixed.  About a month ago, the same thing started happening again!  It's only happening to the left side as it did the first time.  Something else I should bring up is that I have a few gigs where i'm only able to use 1 Turntable and end up using the one side.  Meaning that I definitely use the left side more so than the right.  

I'm wondering if anyone else has experienced this, or if i'm just really unlucky to have the same thing happen twice.  I asked some of my dj friends, and none of them have experienced this.  

Thanks,

Umesh