Cormac McLaggen Repeat Year
tldr - why do we see Cormac in movies 7 and 8? He should have graduated in book/movie 6.
In the books Cormac is supposed to be a year ahead of the trio in 6th year, meaning it’s his 7th and final year in book 6.
But after movie 6 he also appears at Hogwarts in movies 7 and 8: We see him in DH1 when he tells the death eaters on the Hogwarts Express that his father “will hear about this” And we also see him in DH2 clapping in the room of requirement when Harry appears with Neville.
I read on his harry potter fandom page that he has a repeat year but afaik this did not happen in the books and was never explained in the movies.
Does anyone have more information? Why the repeat year? Why did the movie makers desperately need him on screen although it makes little sense for Cormac to still be at Hogwarts. His line could have been said by any student or left out, no?
And yes, I’m overthinking and this is nitpicky. I’m just curious and always want to know more about everything Harry Potter-related.