... maybe they'll actually fix it.
I'm not so sure. I regularly report problems I encounter with the lessons, both with the translations and with the bizarre pronunciations. From time to time I get a message from DuoLingo thanking me for providing the feedback on a translation, indicating that the feedback has been incorporated into the lessons, but I have never received such a response on pronunciation feedback. It might actually be better if DL would state right up front that they don't plan to do anything with corrections we provide for pronunciation bloopers, and we could stop wasting our time trying to get the staff to fix them. I should say that my wife and I do find them a rich source of hilarious entertainment (though they're not doing beginning students any favors by misleading them on how French should be pronounced). I did get a clue, reading between the lines for one of the forum comments from the staff, that they're dealing with an awkward personnel problem, which I took to mean that perhaps they are running into difficulties replacing a speaker who keeps making these sorts of mistakes. You'll note that the original comment at the top of this thread is four years old, and the problem still hasn't been corrected, so perhaps there's some truth to this speculation.
My question to the Duolingo team: Since the French course has both a male and a female voice, in the case that one voice is correct ([misperceived sexism aside] usually the male, as in this case) and one incorrect (usually the female), can't one of the voices simply be disabled for an individual sentence? If so, why has this not been done yet for this sentence (and plenty of others in this course)?
It might be DL actually preferring "stronger", which is certainly a more direct translation. Or it might be DL not yet having put "greater" in its list of acceptable alternatives.
Perhaps a passing Francophone will have an opinion about the suitability of "greater" in this sentence?