User blog comment:G0LD3NF1RE/Dawnguard encounters issues with Playstation/@comment-2.99.111.119-20120903124254/@comment-71.226.105.81-20120903172336

That'd be my guess. Wasn't it the same way for Fallout 3 and Elder Scrolls 4? Bethesda waited until all the DLC had come out, and the not only made it available for download, but also came out with it completely packaged. Or maybe I'm thinking of something else. I know partly because PSN was down, some of New Vegas's DLC had to be pushed. Bethesda and Sony just have a rocky relationship, I guess.