I haven't tested this thoroughly, so I can't say the exact steps how to reproduce. I'm also not sure if this is really only on mobile.
But this has bugged me for a while, so I finally decided to write this issue.
Next time it happens to me, I can expand this description.
I'm using HydraPlay on my mobile phone to start playing music
then I just let it play for some time (15 minutes? 30 minutes? enough time for my phone to go to sleep or for me to use other apps on my phone)
then later I reopen the browser on my phone to stop playback or to change the volume, the following happens:
the interface is reacting normally.
when I press the play-pause-button, it toggles between the play and pause visual
when I interact with the volume slider, it behaves normally. I can slide it to a different position
BUT: the actual music playback does not react at all. Volume does not change, playback just continues.
Workaround: reload the web page and everything works again
I haven't tested this thoroughly, so I can't say the exact steps how to reproduce. I'm also not sure if this is really only on mobile. But this has bugged me for a while, so I finally decided to write this issue. Next time it happens to me, I can expand this description.