Got an issue with my Marshall Stanmore wifi speaker. When playing music through Wifi or Bluetooth the volume always goes down on its own. Have to turn up the volume between 5-10 times before it stops turning down the volume on its own. Wifi and Bluetooth connection are fine, it has this issue which each connected device I've tried and with all apps (spotify, Google Music, YouTube,...). Any idea on settings or stuff i can check? Maybe a firmware update something?