Hey Martin,
After checked further, it seems like that is BRAVE browser issue on mobile, for some reason it hitting this following error :
DOMException: Unable to decode audio data
We actually using this wavesurfer-js.org API in the Easysocial, based on what i tested play audio on their sample page here on mobile BRAVE browser
https://wavesurfer-js.org/examples/ , it seems like this BRAVE browser also showing these error on the browser development console tool, you can take a look of my attached screenshot below.