I can't tell from the picture, although there MIGHT be a very slight wobble in the lower right hand corner. Be aware that judging is not completely objective. I, and friends of mine, have had one judge make negative comments on something praised by another judge. The extreme version of this was a friend whose quilt was disqualified from the state fari because it was deemed obscene. She entered it in our quilt show complete with the previous critique. The universal view of our show goers and our judge (blue ribbon) was that it was a darling image of her 2 sons building a sand castles. The boys were wearing knee length shorts. If you can't find the problem, don't worry about it. I have had the reverse happen a couple of times. I was persuaded to enter something in a quilt show although I did not think it good enough and I got a blue ribbon, while another, that I thought was a "sure" winner didn't even place.
Your quilt has very strong diagonal lines. While I can't see and clear errors, in person, sometimes minor variations from straight lines are more noticable. If the quilt show is very competitive, sometimes judges need to quibble over very minor details. I have seen the difference between first place and honorable mention be the sharpness of the mitered corners on the binding. My friend who got the HM didn;t speak to me for a week.