"What is a Klingon?"
Do you mean in the full sentence or was it when just the solitary word played? And was it the male voice or the female voice. When the full sentence plays, the nuq sounds pretty clear to me. And when the female voice says the solitary word it sounds pretty good, too. However, when the male voice says the solitary word, it definitely sounds more like nuQ. So if that's what you are referring to, you are correct!
Duolingo has a problem in that when searching for a sound file it refuses to distinguish nuq and nuQ. Both are taught in this course and ideally we should have separate sound files for them. But since Duolingo doesn't recognize the difference in the sound files we have no way to make it play separate files for them. It's not that big a deal for full sentences since it is unlikely you'll ever get a full sentence which is differentiated only by a q versus Q. But there are a number of words taught in this course where an identical word, except for the capitalization of the q/Q is taught. So, for now, throughout this course, when you get the sound file for a solitary word with a q or Q you might wind up with Duolingo playing the wrong one for you.