Here's a really, really bizzare error that I heard about from one of my cousins: Last summer, my cousin and one of his children went to visit my mom's father at a hospital in Miami. The hospital has a children's area for the younger patients visiting the hospital which they passed by whenever they had to visit my mom's father since his room was nearby. The TV in that area used to play Cartoon Network all the time (and occasionally ABC Family during Christmas, as seen in a photo that used to be on their site. For those curious, the thing shown was The Year Without A Santa Claus) until one day when something happened during an airing of the Teen Titans Go! episode "Caged Tiger". During the scene where Beast Boy wet himself, the line he said (I don't know what the exact phrase was-can anyone help me so I can put in how it would have sounded?) was cut after the first two words of said line, which was followed by a few seconds of a black screen and the Family Guy theme song. However, they changed the channel during the chorus to Disney Channel (which was showing the movie Lemonade Mouth), so I have no idea if it was fixed or not. And this wasn't at a time when Adult Swim was going to come on-this was in the very early afternoon, so it might have been a case of confusing AM with PM like the local ads error on "To Catch A Fairy".
Speaking of TTG, I was waiting for High School Musical to come on and flipped through the kids' channels to see if anything interesting would be on the next day when I saw my guide list that this morning, there would be ELEVEN airings of "Serious Business" and "Caramel Apples". I checked LocateTV and TVGuide, and only TWO airings of these episodes were schedule. When I checked just now on my TV guide, the error was still there. If they really aired these episodes eleven times, I wouldn't be surprised. They once showed "Puppets, Whaaat?" for six hours according to reddit.
Sheer irony here: As I was trying to post this, a video ad for TTG played on this page!