Continuity mistake: When M'Baku challenges T'Challa, the decorations near his neck are in a different position between him facing the crowd, and him turning to face T'Challa.
Factual error: During the mid-credits scene T'Challa is addressing the United Nations about Wakanda's true nature. A Welsh flag can be seen among the other nation's flags, which would suggest that Wales is a separate nation from The United Kingdom - not the case.
Continuity mistake: When Ross is interrogating Klaue, there's a shot from behind him and we can see the bug on his left shoulder. When he leaves the room and talks to T'Challa, the bug has vanished, but reappears again shortly afterwards.
Answer: Well he's not literally an uncle to Killmonger, but rather he saw him as a surrogate uncle when he was a kid because he was always by his father's side.
Phaneron ★
And yes, he did know.
lionhead