The Starbucks cup.
If you're paying attention to the Internet in any form or fashion, you know what Starbucks cup I'm referring to. It's that Starbucks cup that snuck into a Game Of Thrones episode (S8, E4). There's no need to rehash what really happened. That was just a silly mistake.
What's interesting to me is how the industry responded. HBO actually removed the Starbucks cup within a day or two - and replaced the file on its streaming service with a corrected version of the episode. It didn't take long for HBO to acknowledge the mistake and then repair it… “doing it live,” so to speak.
…and I think this sets an interesting precedent. I'll call it DevOps for Film - or more specifically, FilmOps.