Yep. Shouldn't have accepted it.
The question was what does AM stand for. The contestant said "anti-meridiem". Alex said, "We'll take it. Anti- or ante meridiem."
But "anti" with a long I isn't an alternate pronunciation of "ante" (with a long EE) - though the reverse can be true. And "anti" and "ante" are very different words.
Ah... Upon further reflection, the judges have decided not to accept it. Yes!