I'm going to assume you checked for a pop-up menu to ensure it's in fact a Blu-ray (if you purchased it on ebay etc)
Other than that...... maybe you are just more attuned to the details, and are noticing flaws that you didn't before, or not seeing clarity you thought you saw the first time.....
basically I have no idea.... never heard of a bad disc causing poor PQ... it either plays, or it doesn't
