Marvel spent six years fixing a continuity mistake that lived in one out-of-focus background shot, and the fix cost exactly one word.
In 2011's Thor, the Infinity Gauntlet sits on a pedestal in Odin's vault for about a second while the Destroyer walks past. Infinity War was, in Kevin Feige's words, barely a glint in the studio's eye. The prop was a treat for comic readers. Nobody had mapped out who would eventually wear it.
Then Age of Ultron ended with Thanos pulling a gauntlet out of his own vault in 2015, and Marvel had two.
Feige's first public answer was "there are two gauntlets." The internal creative group had a better theory. Odin faked it. If Asgardians knew a weapon existed that could erase them with a snap, they'd start asking whether Odin could actually protect them. So the All-Father displays a replica and tells everyone it's handled.
Ragnarok turned that bailout into character. The whole film is about Odin's lies. Murals painted over, a firstborn daughter scrubbed from history. A counterfeit weapon in the trophy room fits a king who built his reign on curated history, so Hela knocks it over, says "Fake," and the retcon doubles as a character beat.
Ragnarok co-writer Eric Pearson said the line also cleared the board for Markus and McFeely, who were writing Infinity War at the time, a film where Eitri forges the real one at Nidavellir with no Asgardian original cluttering continuity.
The tell was in the prop the whole time. The 2011 gauntlet is a right hand. Thanos wears his on the left.