It's very common for web pages to have errors in their markup. For the most part, these errors go completely unnoticed and our detection algorithm doesn't skip a beat. However, during some testing we ran today, we noticed one detection method was misbehaving for a particular url. Upon further inspection, we found that a small error in the page's markup was at the root of the problem. Once we found the cause of the problem, coding the fix was a breeze.