Using Spotify 126.96.36.1999 on Nexus 6P and 5p on OS 7.0. Problem started about a month ago (with an earlier app version). Playing music from Spotify to Chromecast audio cuts out after 15-30 minutes. When I return to the app to restart the music no Cast enabled devices show up in "Devices available" list. However an instance of Spotify running on a desktop on my network does show as available. Other cast capable apps (like GPM) can see the Chromecasts on my network without issue. Only by killing the Spotify app (by swiping it away in the recents menu) and restarting it restores it's ability to see the Chromecasts again but only for 15-30 minutes. Any ideas? I've attached a short screen capture video to demonstrate the problem more clearly.
2016 12 07 10 03 04-1.zip