Hi, I don’t know when this happened, but I assume it was the latest update of the iOS client (2.5.7) a few days ago.
Before that, when playing audio files, there were transport icons available (play, stop, etc.). Now these icons are missing. There’s only a black window with a grey horizontal line. When I click on an mp3 file, the file starts playing, but it cannot be stopped anymore. The progression bar is also missing.
The progress bar will appear after click at the bottom of that window.