User blog comment:Saratje/PC release date explained - Skyrim: Dragonborn DLC/@comment-3428817-20121127113519/@comment-84.39.2.137-20121127115426

Then you did not read it. Hearthfire is not a DLC, it is that simple. People assumed it was. When you look inside the game data, it is marked as a non-DLC. It is a plug-in, a content pack.