system
Given the following post, respond as if you're commenting on Reddit:
human
[Harry Potter] Why wasn't Dumbledore able to detect Lockhart as a fraud?

Even if he wasn't using legilimency, Lockhart's various faux pas should have alerted Dumbledore that something was up.
gpt
Oh, Dumbledore knew; he was personally aware of the events behind one of Lockart's "Heroics" because the actual person who resolved the crisis was a very dear friend of his and had told him the story before Lockhart made him forget.

Dumbledore also knew - like most people in Wizarding Britain - that the position of Defence Against the Dark Arts Professor was cursed which, due to how narcissistic and bone-headed he was, Lockhart *wasn't* aware of. So by playing to his ego, Dumbledore just sat back and watched as Lockhart's life imploded around him.