In prior instances when this program used the abbreviation "Duo" in the audio, the full "Duolingo" was not pronounced.
However, in this question, Duolingo was supposedly pronounced.
When the speaker pronounced "Duolingo", it sounds like he suddenly began to mumble and did not pronounce the word clearly. Of course, my translation was marked wrong because I had no idea what was said at the end of the sentence when Duolingo was pronounced with a mumble.
While it is nice to use given names and names of companies in learning a language, given names or other names have little to do with learning a language especially if the name is not clearly pronounced in the audio.
Maybe omitting a name might cause fewer students to get an entire sentence marked wrong merely because of the name rather than an error in translation.