When Im listening to music and a notification is coming in, the volume of the music is lowered, but the notification is not played. This is really annoying when Im in the car and the navigation app (Sygic) is trying to tell me where I have to go or when Runtastic tries to tell me some statistics.
When I listen to music via other apps, e.g. Poweramp, the notifications are working fine
Please read the guide linked below for details on the most common issues and how to fix them. Usually a clean install is the first step to take and resolves most of the usual issues; the guide details the steps to take to ensure a full 'clean installation' is achieved - This includes checking redundant folders and a REBOOT!
Its not the problem with a clean install. Im facing this bug since I started to use Spotify in last November.
In the time between November and now I ran the Stock-LG-Rom (Marshmallow), CM13 (Marshmallow) and now Exodus 6 (also Marshmallow). Sometimes I restored Spotify from a TitaniumBackup, but I also tried it with some clean installs.
The notification bug seems also to be on all applications. For example also on "Disa" (messenger) and Nine (Exchange Client)