No, because the imagery isn't just "off", she has to come up with it all on her own. All she gets from other people are the things you can read. And honestly, some of that may be stuff she comes up with, like dialogue within an imagined scene.
So she is, with just a little prompting, generating perverted scenes in her mind. Sure, he's thinking about lewd stuff, but she's creating the mental porno. If she wasn't at least as lewd as he is, most of that would be a lot more tame.
...There's no twist here if he was, in fact, thinking lewd stuff, though...? Like it just becomes "her imagery isn't accurate", and, "her imagination of what the guy she knows is thinking lewd things might be thinking, is vivid". That doesn't even end with concluding
she is horny, much less that he
isn't (the supposed twist).
But also, separately: You're now thinking of taking it all the way to "everything she parses from him is potentially made up, not just the images, so long as there's some vague tenuous connection to what he's thinking"
And sure, yeah, that could fix this whole problem if taken far enough—but then if the readings she has of his and others' thoughts are that far divorced from peoples actual thoughts and so unreliable in every aspect, it immediately opens up other plot-holes—most importantly how and why she's reading everyone else's thoughts so closely and accurately in all other circumstances.
And honestly: An author could still navigate all of that and retcon it
successfully with the right excuses. It's doable. But the legwork hasn't been put in here and it instead seems more to just be hoping the audience doesn't remember all the details that would make the proposed explanation problematic.