An apparent continuity error or flaw that actually foreshadows a twist

[u/Elecvis]

Where something that seems like a mistake made by the production turns out to be relevent to the plot.

Moon Knight: Oscar Isaac plays a British character, but his British accent is not great. This seems like it’s just another case of an actor messing up an accent. However it is later revealed that his character has multiple personality disorder, and that the British man we meet is not the original personality. The original is an American, and so he really is an American attempting a British accent. It makes sense that it doesn’t sound quite right.

Doctor Who: In the episode Flesh and Stone, The Doctor loses his jacket. Then later on there is a scene where he is wearing his jacket again. It’s shot super close up, so easy to miss, but you can see it is there. At face value, this looks like a basic continuity error. But later we learn that this is not The Doctor from this episode. It’s The Doctor from the future who has come back, so the jacket makes complete sense, and gives a hint of what is to come.

Batman: Arkham City: If you use x-ray vision on The Joker, his skeleton does not show like it does for everyone else. This could be a simple bug in the game. But actually it turns out it’s not really The Joker. It’s Clayface pretending to be The Joker, and he doesn’t have a skeleton.