One track motor stronger than the other?

I experienced recently with my Kubota U50 when giving full power ahead on both tracks pushing against a large boulder, that the left track spun quite easily, while I did not get the right to spin at all. Similar gravel underneath the tracks and better tread depth on left track.

Could there be some damage/wear on my right final drive? Does anybody have experience on this field? Appreciate any/ all tips:)