Why does the volume adjust on google play music

[bigguyharleyrider]

when I'm on Bluetooth using Google Play Music through my Galaxy S8+ in my Dodge Ram whenever a text message comes into the phone the volume goes down and wont go back up again...wtf is going on?? Drives me nuts

 

[B. Diddy]

Welcome to Android Central! Could it be that the car system is waiting for you to act on the message? Does the text show up on the car screen, and if so, what happens if you dismiss it?