definitely a defect. I had this cab and the bass sounded great. I got is used, so the speakers were already broken in. Not liking the speakers is a personal taste, but there is no lack in any frequency really, just like v30's. They sounded as full as mesa v30's but with more speaker breakup., due to the lower wattage rating.
What you describe reminds me when I once wired a 4 x 12 wrong and it had no bass at all, but I couldn't tell it was wrong until like a month later. I thought that greenbacks just sounded very thin.