It can't be easy keeping the threads of the Marvel Cinematic Universe in line. Over 10 years and 19 movies, the MCU has fashioned itself a multi-billion-dollar gilded tower with which to look down on other franchises. The people in charge of keeping the threads all headed in the same direction do not have an easy job.
Avengers: Infinity War, the 19th MCU film and the largest by far, has to have been the hardest movie to keep in line yet. It's also home to a major inconsistency in an important plot device. It turns out Thanos' Infinity Gauntlet, the ostentatious golden glove Thanos uses to harness the power of the Infinity Stones, should never have been seen on screen before Infinity War.
**SPOILER WARNING: This post contains spoilers for Avengers: Infinity War.**
We first saw the Infinity Gauntlet during Avengers: Age of Ultron's mid-credits scene. Thanos unlocks at least four different shiny vault doors to get to the Gauntlet, which sits on a pedestal. He shoves his hand into the glove, closes his fist, and growls out an oath: "Fine. I'll do it myself."
This oath was supposedly in reference to Ultron's failure to wipe out humanity, the genocidal version of "It's hard to find good help these days." While the sentient demon robot's plans were a bit less lofty than Thanos' — wanting to kill everyone on one planet versus wanting to kill half of the universe's total population — this mid-credit sequence makes it seem like Thanos was definitely paying attention to Ultron's plans and the Avengers themselves. That makes sense, as one of the Infinity Stones was so crucial to Age of Ultron's plot.
If his comment is in reference to the events of Ultron, then we can presume this scene takes place directly after Ultron. That also makes sense.
What doesn't make sense, though, is why Thanos has the Gauntlet at this point in time. Because, technically, the Gauntlet wasn't supposed to exist at this point, as laid out by Infinity War.
Eitri made the gauntlet for Thanos during or after Thor: Ragnarok
In Infinity War, Peter Dinklage's Eitri reveals that Thanos came to Nidavellir and forced the Dwarves to make a device that would help him harness the power of the Infinity Stones — thus, the Infinity Gauntlet was born. Then, upon the device's completion, Thanos killed them and left them to ruin.
It seems Eitri was the only one who made it out alive; he takes his anger out on Thor, demanding to know why Asgard didn't come to their defense as promised. Thor tells Eitri that Asgard was destroyed (i.e., Thor: Ragnarok happened). This means Thanos laid waste to Nidavellir during or after Ragnarok when the Asgardians were too caught up in their own destruction to guard any other part of the nine realms.
But wait. If Eitri and the dwarves made the Gauntlet for Thanos — from scratch, mind you, as Eitri implies he came up with it right then and there to solve Thanos' desires to control all the Infinity Stones — during Ragnarok, then why did the Gauntlet exist at all in the MCU before Ragnarok?
In Ragnarok, Hela (Cate Blanchett) wanders through Odin's vaults looking for the Eternal Flame and comes across an ultra-shiny version of the Infinity Gauntlet (with the "Infinity Stones" in place, mind you). She declares it a "fake" before pushing it haphazardly off its pedestal.
No one doubted Hela for a second that the Gauntlet in Odin's vault was a fake. After all, we'd already seen the Gauntlet at the end of Age of Ultron; we knew Thanos already had it because that's what all of these dang movies had been leading up to.
But Infinity War retconned that.
The question becomes why a fake version of the Gauntlet was in Odin's vault at all if Eitri hadn't even created it yet (or was in the process of creating it during Ragnarok) for Thanos. That meant Odin had a fake of something that didn't exist, which really doesn't make sense.
And if Eitri and the other Dwarves didn't make or imagine up the Gauntlet for Thanos until Ragnarok was going on, then why did Thanos have the Gauntlet at the end of Ultron? We've already established that the Ultron post-credit scene was in direct reference to the events of Ultron and not a flash-forward.
That leaves us with one answer: Infinity War retconned everything we thought we knew about the Infinity Gauntlet before Infinity War, ignoring any hints dropped by the previous 18 MCU films.
An aside: Ragnarok director Taika Waititi 100 percent does not care about this inconsistency, by the way. For him and the Ragnarok crew, it was a well-timed, funny aside to tease at the other MCU films. In Waititi's famous words:
This is nitpicking at its best — nitpicking for the sake of nitpicking. The Infinity Gauntlet's timeline and when it was created and when it fell into Thanos' grasp isn't, in comparison to anything else, important. But, it still exists. The most important part is that we acknowledge it and move forward.
After all, this doesn't really change anything. Half of your faves are still dead.