First I have to say that I am a great fan of the podcast and really like the courses topics, but I just wanted to try the first free course about responder on my iPhone XS and I have no sound. If I open the website (even inside the app) everything works fine, so definitely not a problem with my iPhone speakers ;). But the downloaded courses just have no sound. And I‘m no designer, but the app UI could need some polish the yellow on gray colors really hurt my eyes. I will rate this back to five stars as soon as I am able to use the app.
Edit: Back to four stars I figured it out, it seems the audio output is respecting the silence mode of my iPhone, this might be a feature, but doesn’t fit the normal behavior of other apps, so I think this qualifies it as a bug.