Definitivamente aconteceu, pelo menos uma vez.
Em " The Leaky Cauldron e Mugglenet entrevista Joanne Kathleen Rowling : Parte Três "(The Leaky Cauldron, 16 de julho de 2005)
ES: ... [the third question] It’s the one about Grindelwald, which I’m sure you’ve been gearing up for us to ask.
JKR: Come on then, remind me. Is he dead?
ES: Yeah, is he dead?
JKR: Yeah, he is.
ES: You don’t have to answer but can you give us some backstory on him?
JKR: I'm going to tell you as much as I told someone earlier who asked me. You know Owen who won the [UK television] competition to interview me? He asked about Grindelwald [pronounced "Grindelvald" HMM…]. He said, “Is it coincidence that he died in 1945,” and I said no. It amuses me to make allusions to things that were happening in the Muggle world, so my feeling would be that while there's a global Muggle war going on, there's also a global wizarding war going on.
É claro que, como sabemos pelas Relíquias da Morte, Grindelvald definitivamente não estava morto em 1945, já que ele é mantido em Numengard após ser derrotado por Dumbledore; e só será morto em 1998 por Voldemort.
ATUALIZAÇÃO:
Defina a ironia : em essa mesma entrevista mais tarde, JKR disse o seguinte:
JKR: I've never, to my knowledge, lied when posed a question about the books. To my knowledge. You can imagine, I've now been asked hundreds of questions; it's perfectly possible at some point I misspoke or I gave a misleading answer unintentionally, or I may have answered truthfully at the time and then changed my mind in a subsequent book. That makes me cagey about answering some questions in too much detail because I have to have some leeway to get there and do it my way, but never on a major plot point.