There may be a Captain Marvel plot hole in play, or simply an open mystery that will need to be fixed in a future film.
It’s very similar to a debatable issue with Thor in 2012’s first Avengers movie, released in the UK as Avengers Assemble.
When the God of Thunder came to Earth, he had seemingly forgotten all about how he left things with Jane Foster (Natalie Portman) in his own solo movie.
And though that was briefly addressed in Thor: The Dark World, it felt odd at the time that Thor didn’t mention Jane once, or make time to see her, once he managed to get to Earth.
Now, Carol Danvers is in a similar situation in Avengers: Endgame.
At the end of her 1990s-set solo movie, she leaves the planet to work intergalactically.
But why, when she finally does return to Earth in Avengers: Endgame, does she not mention – or seem concerned about – the likes of Maria Rambeau and her daughter Monica?
Carol and Maria pair are established as very close friends in the solo film, so would Carol not have sought them out upon her return, or at least enquired over their wellbeing when she learned of the Snap?
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Perhaps that’s an issue that will be resolved in a future film – as to whether Carol and Maria made contact off-screen, or something happened in between the events of Captain Marvel and the events of Avengers: Endgame to explain it.
Meanwhile, a new fan theory highlights another potential issue with the film’s ending.
WARNING: Massive spoilers ahead.
Ahead of the film’s climax, Bruce Banner – as Professor Hulk – successfully reverses the Snap, by pulling off a Snap of his own.