User blog comment:Rappy 4187/Technical Update: September 16, 2014/@comment-3183960-20140917141432/@comment-126761-20140917150134

Hey, this is related to a fix we made for videos, to make them clear content before and afterwards (it was having some rather bad effects on the video overlays beforehand). This appears to have been an unintentional side-effect - I will inform the technical team, and we'll see what we can do.