LOL ... Guys ... watching too much FoxNews, listening to InfoWars and reading Breitbart & WikiLeaks.

Not everything is a conspiracy theory, or every action having causation in some other yet simultaneous (but independent) action.
Stop imagining causation where there is absolutely none!
Mr. Taylor's departure has been od the AvH's desk for quite some time now ... But it has been agreed he would stay for Cullinan's launch, and then he could be released immediately. It wasn't announced earlier exactly because of the then upcoming premieres the Cullinan - not to undermine Mr. Taylor's role & authority as RR Chief designer. A wise move IMHO. Otherwise more focus would be on him leaving (why and where to) instead on Cullinan itself.
Mind designers / design chiefs constantly seek new challenges. And not much challenges @ Rolls-Royce right now - after Dawn, Vision 100, new Phantom, Cullinan, and new Ghost (design process finished). A perfect time to go & to seek new professional challenges. Mr. Taylor has done excellent job @ RR, and he can now move on.
I despise some "journalists" who tend to produce sensationalist titles, using words like "abruptly" , "surprisingly" , "unexpectedly" etc ... implying some sort of scandal, argument, wrongdoing etc. ... just for the mere purpose of click-baits.
Information pimps - that's what they are.