I suppose my honesty will be the death of me.
I didn't want anyone to think they would be getting a new factory-sealed disc and feel cheated.
The defect is a glitch at about the 34 minute mark (when Alex attacks his fellow droogs and throws them in the river). On two different players, the movie froze at this scene and had to be forwarded past it by a few seconds. One player handled it better than the other. Actually, I need to check it again after cleaning the disc. I assumed it was defective because it froze up on the first play out of the case, but maybe some gunk got on it somehow.