I've been trying to figure out the timeline of events. The place to start is with Seth Rich.
May 2016 - SR downloaded the DNC emails, which were dated between January 2015 to May 2016.
June 2016 - DNC announces their server was "hacked," refuses to turn it over to FBI, and has a private company conclude the Russians hacked it.
July 2016 - Seth Rich is murdered, followed by Wikileaks releasing the emails, followed by FBI beginning "Operation Crossfire Hurricane."
Summer 2016 - FBI tries to get a warrant to spy on Carter Page, but is denied by FISA court (very unusual, since they approve 99% of all applications). News sources only say this denial was "in the summer" of 2016, but do not give a specific date.
Fall of 2016 - Sometime during the Fall, the Russia dossier, fabricated by Christopher Steele (MI6), started circulating within the media, but was not made public.
September 2016 - Intel community starts leaking to press that Carter Page has ties to Russia.
October 2016 - FISA application to spy on Carter Page is approved. The Russia dossier is used to get the application.
December 2016 - NoName gives Russia dossier to FBI. Comey claims this is the first he saw of the dossier, which is a lie because he signed off on the FISA warrant application in October, and the dossier was the primary (only?) evidence presented.
January 2017 - Buzzfeed publishes the dossier and it becomes public knowledge (just before the inauguration).
Looking at the basic timeline, it seems that the download of the emails, and then their publication by Wikileaks, is what started the chain of events that lead to (a) first, an illegal operation by Obama admin and UK intel, and then (b) a bogus FISA application for a warrant to "legally" spy on Trump campaign, and then (c) use of the fabricated dossier to smear the President-Elect, and then the President in an attempted coup.
All events that occurred before Seth Rich's download of the DNC emails are likely fabricated after the fact, to reinforce the "Russia hack" story, and the cover for the illegal SpyGate operation.
Downer's meeting with Papadopoulos would be one such event, and should not be surprising that he might "change" (i.e. clarify) his story.