Hi, it seems that with the latest update, the volume does not get lowered anymore even with the option checked. To be more specific, there seems to be a delay when the volume is actually changed. So when the device connects but immediately disconnects, the app changes the regular media volume, not the Bluetooth volume, and doesn't lower it. If the device disconnects before the app changes volume, the app won't restore volume back down to its original setting.
https://mail.google.com/mail/u/0/?hl=de&shva=1#label/%40darken.eu%2Fsupport/160d9f13a18e63a0