Not really. During the commercial breaks, Alex frequently re-records clues if he stumbled over the wording, and then they just dub that in over the vocal of his original reading. The public never hears Alex’s original clue-reading, but there’s nothing unethical about that. It just makes the show run more smoothly.
When I was a contestant, one of the things they told us in the pre-show briefing was, “If there’s a discrepancy between the text of the clue as it appears on the monitor, and the way that Alex reads it, go with what Alex says. There may have been a last minute change in the wording.” In such cases, they re-edit the onscreen text when the show is finally broadcast. That’s what I imagine happened here.
In those cases, like this one, where such errors actually affect the outcome of the game, they usually attempt to remedy this by inviting the contestant back.