Spotify switch back to mobile phone output when playing via SpotifyConnect and the phone is unlocked

[hifibastel]

The connection is lost when i unlock my phone via pin or fingerprint.
This happens on my Denon AVR-7200WA.

If this happens Severin times, I have to restart my phone and Receiver to connect again. This behavior I have for several months.

It won't happen when playing via Bluetooth or google chromecast.

Spotify: 8.2.0.788 armV7
Phone: Galaxy S6 Android 6.0.1

I have found this issue several times but it was never answered and marked as closed.