When Shuri gives T'challa the new shoes (called sneakers), she mentions that they absorb sound & allow silent footsteps, which T'challa demonstrates. Later in the film, T'challa runs up a ramp wearing the sneakers... accompanied by the sound of footsteps.
Killmonger is said to have "graduated from Annapolis at 19". Annapolis refers to the United States Naval Academy in Annapolis, Maryland. They do not allow anyone younger than 17 to enroll, nor can you graduate early due to its rigid four-year academic program for its midshipmen.
When T'Challa is addressing the UN, a Welsh flag can be seen among the other flags in the background.
As a part of the United Kingdom, Wales doesn't have UN membership in its own right, so this flag would not be displayed.
With all the advanced Wakandan technology and medicine, and the accepted policy being to keep it all secret from outsiders, there is no reason for Shuri to even let Agent Ross regain consciousness while in the country, let alone spill any secrets once he does. The logical thing would have been to keep him sedated, tell him nothing and wake him up outside of Wakanda.
During the scene where Ulysses Klaue is being interrogated by Everett Ross, you continue to hear Klaue speak whilst the camera is shown outside the interrogation room, with the camera focused on T'Challa. When T'Challa begins to walk, you can see Klaue behind him and whilst you can hear him still talking, his lips aren't moving within the interrogation room in the background.
The beard of Chadwick Boseman changes in length from take to take. At the beginning of the movie, at 7:58 it is long, then at 8:06 it is short, then at 8:11 is long again.
When Everett K. Ross enters the interrogation room he has the listening device on his left shoulder. When he leaves the interrogation room, it has vanished. But when the scene cuts to a different camera angle, you can see the listening device again (it is out of focus though).
One Wakandan subtitle has a misspelled word: "descendant" appears as "descendent".
The opening sequence showing the Earth from space as the vibranium meteor crashes into Africa shows the modern globe, even though millions of years ago continents had noticeably different shapes and positions. However, the sequence clearly shows not a real Earth, but a representation of Earth in the imagination of the child who is listening to the story. It's obvious, since this imaginary Earth has neither oceans, nor atmosphere, nor vegetation.
After Killmonger wins the challenge against T'Challa, the leader of a tribe goes to put a necklace on Killmonger with shaking hands. In the first shot, she is holding a necklace with a short cord and a metal lobster claw clasp. When she puts the necklace on Killmonger, the necklace strand is much longer and made entirely of rope.
During the duel between T'Challa and Killmonger, both repeatedly switch between wearing black trousers and black shorts, depending on the camera angle and the editing.
None of the items in the London museum African exhibit have any labels indicating item type or tribe affiliation. Every museum would have that in their exhibits.
Whem M'Baku challenges T'Challa he refers to the blessings of Hanuman, the monkey god. When the queen of King Ram (of India) was kidnapped a monkey was found in the forest with her scarf, indicating a route that pointed to the the King of Ceylon (Sri Lanka) as the kidnapper. By saving the queen the monkey was given the name Hanuman. Hanuman is not the name of an African monkey god, but of India.
When T'Challa and Killmonger duel for the throne, T'Challa slashes Killmonger in the cheek, resulting in a bloody gash. Shortly after, there is a split-second cut that shows Killmonger's face without that gash (this is difficult to notice unless you pay close attention), but then the next shot of him shows the gash back in its place.
When Erik Kilmonger finally dons the black panther suit, he is well clothed. When the sonic stabilizers deactivate his suit during the final fight, his bare skin is revealed and you can tell that he is not wearing a top. That's because his clothes were clearly disintegrated as the panther suit was forming.
The blankets are not worn properly. Rather, they are arranged like western shawls.
The mixture of languages and occasional use of single words can be very odd. For example, when Zuri congratulates T'Challa, the latter responds with "mzuri" which is Kiswahili for "good."
When Killmonger picks up the woman in a choke hold, she is initially squirming around in the air. When the camera cuts back to Killmonger, the woman is motionless - either she accidentally stopped squirming around for that shot (continuity mistake), or he switched to holding up a dummy instead.