In the brief period where my premium expired, I noticed that the banner ad in the background, which I presume was for Rift, seemed to be screwed up. The right side was on the left side and the left side was on the right side, and there was a line about 3/4 of the way from the left orientation where the two sides were meeting in a seam.
This may have been due to adblock causing the burp as well, although I could have sworn I had Zam whitelisted (not that it matters 99.99% of the time for me.)
I should have grabbed a screenshot but I was more concerned with making the ads all go away than I was accurate error reporting at the time.
Using Google Chrome 15.0.874.106 m