Warning: Contains SPOILERS for Guardians of the Galaxy Vol. 3!Nebula taking Bucky's arm in the Marvel Cinematic Universe keeps getting weirder, as Guardians of the Galaxy Vol. 3 missed a chance to pay off the moment. The final chapter of James Gunn's Guardians of the Galaxy trilogy prioritized wrapping up the main story revolving around Star-Lord, Rocket, and the rest of the team that has taken place in the prior two movies and a few other MCU appearances. However, the director also used The Guardians of the Galaxy Holiday Special to set up several key developments for Guardians of the Galaxy 3, such as Mantis and Star-Lord being siblings, Cosmo being on the team, and more.
https://screenrant.com/gotg-3-nebula-taking-bucky-arm-weird/