In fact, everything here may be very simple.
When the dev made the last update with a trip to the club, in ended he announced the release date of the "DLC" with Anya, i.e. in essence this event most likely should have been included in the update as part of its content, as well as the second "DLC", but the dev didn't have time get it in on time for release! In essence, these two "DLCs" are a logical ending to the last update and why it's called "DLC" is the question here is not clear, after all, these two add-ons could have been called version 0.5.1 and version 0.5.2, for example.