Not everyone is who they say they are
At first the sample feels right. It comes back filled, the answers make sense, and you can already see how the story might come together.
Then you spend a little more time with it and something starts to feel off. It’s all a bit too clean, a bit too certain, like the edges have been sanded down and the contradictions never really show up. So you go back through it again, and what felt solid at first starts to loosen. The story is still there, but it only really works if you don’t look too closely.
And that’s the problem with bad sample, it can pass at a glance, right up until you actually try to rely on it.