Even before the release of the film, it seemed clear that the Avengers wouldn't exactly survive Captain America: Civil War. Divided over the Sokovia Accords and Bucky Barnes, Captain America leaves the superhero team he helped create behind at the end of the film after a climactic battle with former friend Tony Stark.
At least, that's what most fans remember. But one small detail noticed by a fan on Reddit points towards Captain America actually leaving the Avengers behind far earlier in the film.
If one looks closely at Cap's costume while he battles Crossbones in Nigeria, an Avengers patch can be seen on Steve's left shoulder. Later in the film when Steve goes out on his own to find Bucky, that patch is gone, never to be seen again for the rest of the film.
There are a couple of ways to read into that little detail. The first is the most boring and mundane explanation: perhaps Steve simply has two Captain America outfits, and the one he wears in the second half of the film doesn't sport an Avengers logo. It sounds goofy, but it also seems unlikely that Steve only owns one version of his costume. What if it gets damaged? Surely he has to wash it at some point, and if so, what does he wear while saving the day while his costume is in the washer? Having multiple costumes only makes sense.
In all seriousness though, a more likely answer could be that Steve removed the patch not because he had already decided to quit the Avengers, but because he didn't want the Avengers to be blamed for Steve intervening in Bucky's escape. Removing the patch was Steve's way of saying he was acting alone in his actions and not as part of the official Avengers team, though the rest of the world probably didn't view it that way, patch or not.
The third possibility is that Captain America did indeed decide his time with the Avengers was over much earlier in the film, removing the patch as a way of forever severing his ties with the superhero organization. He might have seen the rift between his supporters and Iron Man's as too large to repair even before the fight between the two.
Regardless, the Avengers as fans know it is no more by the end of the movie. Steve even drops the mantle of Captain America, relinquishing his iconic shield before breaking a number of fellow heroes out of a government prison in the middle of the ocean. Though the Avengers will no doubt reunite to take on the Mad Titan Thanos in Avengers: Infinity War, this newly discovered detail just goes to show that Steve was more than ready to leave the Avengers behind if it meant doing what he thought was right.