@Stefan-Daniel1,
It's quite easy to forget about the non-refundable discount. Airbnb is the only platform that doesn't clearly state that it's a non-refundable discount on reservation details page. Also, Airbnb manages the refundable rate differently than other platforms by only displaying for dates that are within 60 days from the arrival date.
I have submitted suggestions to Airbnb that when the non-refundable rate is selected that there is should be a non-refundable discount listed in the discount area that is automatically checked. I have also requested that non-refundable rates be displayed for all dates on a calendar. So far, these changes haven't been made, but maybe one day.....