Plan

Premium

Device

Huawei, Samsung, OnePlus

Operating System

Android 10

Spotify version 8.5.74.834

Harman Kardon Towers with Google Assistent and Spotify

My Question or Issue

Normally the volume buttons on my Android phone control the media volume of videos/media that I play on my phone. Lately, however, the volume buttons control Spotify volume when music is playing via the Google Assistant HK Speakers (increasing/decreasing the HK speakers, not my phone). You can see in the screenshot how there's a casting symbol for volume control. I know it is the Spotify app and not Google Home or Chromecast, because when I go offline on Spotify the music keeps on playing on the Google Home HK Speakers, but i can't control the volume via my phone anymore. 

So, how do I set the volume buttons on my phone to control the media from my phone instead of the volume from the Google Home HK Speakers?