Thread:Elledy92/@comment-26838855-20190425183005/@comment-2106279-20190521093654

The writers aren't sure of it entirely + have zero explanation for the shield. Yeah, I know you headcannoned that the Wakandans fixed it, but that's you filling in a blank. The Russos are surefire & steadfast in their explanations & even explain how come Cap's shield is fixed again.

For the time being, it seems the Russo explanation is the canon one here. Like Elledy said, it depends on a third party. Someone informed Feige about Markus-McFeely & Russo brother contradictions during his AMA Reddit and asked him to weigh in, and all he said was "Yes."

As in it basically went like "the writers and directors have completely different explanations for time travel and the film's ending! Which explanation do you think is the most true?" and then Feige replies "Yes." and then moves on to the next question. Answering the question without really answering the question. 'Cause let's face it, whichever one Feige agreed with would be the canon explanation.