Oh wait what? I didn't even know this was a thing, I don't follow Pottermore or anything. XD
That being said, while it is a bit careless to do something like that, at the same time it's not THAT bad. Exact numbers and tiny details like that never mattered that much to me.
I was just more annoyed that she tried to slip it under the rug instead of just call herself out and publicly retcon something from the books. Like, if you're changing a detail to work better with your story, fine. Don't try to pretend that it never happened, though.
She got McGonogall's age wrong by a large margin. Like, From what I remember, she wouldn't have even been born for another 10-15 years by the time the movie happened, let alone work at Hogwarts. Yeah, it's kind of nitpicky, but the devil's in the details, and Rowling retconning things in the last few years is the reason why Harry Potter just isn't immersive to me anymore. also the cursed child blows