Although Guardians of the Galaxy: Vol 2 presented some continuity errors within the MCU (for example, the Stan Lee cameo), it was Spider-Man: Homecoming that really caused some issues. The eight-year gap after the first Avengers battle placed the events of Homecoming in 2020, even though they took place a couple of months after the Civil War.
Of course, Doctor Strange could have solved all of the timeline inconsistencies with the Time Stone, causing ripple effects that would be known to the viewers, but not to the characters themselves. But Kevin Feige has a simpler explanation:
"¦only in limited cases do we ever actually say what the actual years are, because we never want to be tied down to a particular year. I think people assume that whenever the movie is released is when is when the movie is taking place, and that is not the case (Screen Rant).
That makes sense. The fans presume that all events take place in a certain year and at a certain point on the timeline. Feige added that the timeline issues will be corrected in the near future with the release of the official Marvel Cinematic Universe timeline:
All of that debate has encouraged us. We are going to be publishing an official – and I'm not sure when, or in what format – an official timeline. It'll probably be a part of…an in-print that you can fold out and look at.
Following Phase III, the MCU will go cosmic like never before (making keeping track of the years even harder), so we assume that we won’t see the official timeline until Avengers 4 hits the theaters (when Earth’s events aren’t at the core of the shared universe).