(Spoiler warning: the theory could contain spoilers for the upcoming Captain America: Civil War movie. Proceed at your own risk.)
Marvel released a new Japanese trailer of Captain America: Civil War, and compared to the previous two trailers of the movie, they had edited one particular scene that contains a spoiler.
Yes, that's the one. Compared to the previous trailer, Bucky has his metal arm back.
This is the shot we see from the 2nd trailer, with Bucky's metal arm stripped of.
Is it that Marvel forgot to add the CGI, which means it's a mistake and it is not a spoiler. Or is it really a spoiler on the fate of the Winter Soldier?
If you haven't watched the new Japanese trailer, you can watch it here.