lol. Well you are talking about the broadcasting of the episode. There were spoilers/leaks of the info about a Dr of color prior to the episode airing.
The best way to approach it is to acknowledge “Continuity” and “Canon” have no real place in Doctor Who. Anything resembling such a thing is ridiculous for show is that is over 50 years old with a good deal of its broadcast history before the age of reruns and home video, or even consistent broadcast history abroad.
It is purely a narrative crutch used when convenient. All of the above theories can be true or it they can just not give any explanation.
MST3K Rules apply. “Just sit back and enjoy the show.”
The BBC’s Eighth Doctor books (which mostly came out before the series’ restart in 2005) positively embraced this, with the punks of Faction Paradox riding roughshod over history and the Doctor’s personal timeline. In one, someone looking into the Doctor’s future was surprised to see he had three ninth incarnations: presumably as portrayed by Christopher Eccleston on TV, Richard Grant in the web-cartoon Scream of the Shalka, and Rowan Atkinson in Comic Relief’s Doctor Who and the Curse of Fatal Death …
The worst drek when it came to Doctor Who books and audio dramas (prior to rebirth in 2005) were the stories which were loaded with attempts at creating continuity or were loaded with fanwank references to past shows. Sequels or prequels to prior broadcast stories.