Isn't this sentence TECHNICALLY wrong for using the subject pronoun "você" in the place of the direct object pronoun "o/a/te"?
We do a similar "wrong" thing in English too: practically no one says "whom" anymore. It almost sounds wrong.
E.g.: "I don't know to whom she was referring." [Correct but stuffy and formal sounding]
"I don't know who she was talking about." [What people actually say.]
Only people who have learned English as a second language (who often speak more correct English than us native speakers) say it correctly.
The wiktionary entry for "você" https://en.wiktionary.org/wiki/voc%C3%AA includes a very useful table of Portuguese personal pronouns showing all possible declension cases. From it we can see that "o/a/te" are respectively the accusative forms of "ele/ela/tu", but none of them correspond to "você". "Você" and "vocês" rather belong, along with "o/a senhor/senhora", "a gente", and "o/a mesmo/mesma", to a class of pronouns that do not decline with case. So, this sentence is grammatically correct after all.
Even if the use of "whom" in English were already in decline, decades of conditioning by the television and movie industries must have taken this word further out of casual speech. Nevertheless, occasionally the writers make an exception and allow a character to speak correctly. It was rather refreshing and not at all stuffy to notice, for example, that Sherlock Holmes in CBS's update of Conan Doyle's character in its popular series Elementary always uses the proper forms of "who/whom".