It is a very old problem, I'm afraid. The female audio is incorrect. Unfortunately, it is part of the audio package which Duolingo uses and cannot be corrected for a single word. I have disabled this as a "type what you hear" exercise.
Please don't report that a known audio issue hasn't been fixed. George (n6zs) already explained that the course editors can't change the pronunciation of any sentence. He has already done everything he can, which is to stop this sentence coming up as "type what you hear".
Only the programmers can do anything more. They could replace the text-to-speech software with a different one, but they would most likely just replace one set of issues with another. There are thousands of sentences in the Duolingo database, and they simply can't verify each one.
I totally understand.
Please leave this as a note for other learners who puzzles about what they hear.
Mustard can also be "hot" in english, for "strong", as in "hot english mustard"
This was an easy one to know that she pronounced "forte" wrong as "forté" Good thing for the words on screen and that it wasn't a listening one only because I would have typed what I heard.