Yes, I was able to reproduce this issue on a Samsung Galaxy Note8 (Android 9). However, the sound begins to stutter for me after about 50 seconds after I put the device into sleep mode. The sound then stops later. This issue does also occure with only one ExoPlayer.
The problem also arises on my device if the app moves into the background (i.e. after pressing the Home button). As soon as the charging cable is connected, the sound starts again. Also when I wake up the device again.
So connect the device to the charger and test …
It seems to be a problem with the energy saving options (on my Galaxy Note8).
