See I really don't think that's the same thing. It's just correcting an error that wasn't caught before it went to print. It's not quite a "retcon". Now, if the solution had been to change the scene in Chamber Of Secrets, then I think it would qualify.
Brony? Moi? surely you jest!
what plot point exactly?
He who fights bronies should see to itthat he himself does not become a brony. And if you gaze for long into an abyss, Pinkie Pie gazes Also
Says the page, "a minor plot point that prefects can't take house points. However, this contradicts an earlier scene in Chamber Of Secrets in which Percy takes points off Ron. Later editions of Phoenix altered the dialogue so that the rule is that prefects can't take points off other prefects. " That's just one example, not the only one on the page.
The example above it, about changing Nearly-Headless Nick's age from Philosophers's Stone to match later-revealed plot events, is closer to being an actual retcon at least.
Maybe it's just me, but I dunno if I'm comfortable with "J.K. Rowling fixed a plot point in subsequent editions of Order Of The Phoenix because it contradicted an earlier book" and things of that nature to be the same trope as "Han Shot First", or jokes changed for being Too Soon in the light of a Funny Anyeurisim Moment. Maybe it's the "Orwellian" in the title - even though the description tries to enforces the tropes are not good/bad mantra, it can't help but carry certain connotations. Anyone else think so?