Issue when plugged in to car AUX - OK Google

[ChristyJade]

Hi, this is driving me and my boyfriend mad as we can no longer listen to music in the car!! 

Every time we play music through Spotify and plug in to the AUX in the car, about 10 seconds in to a song OK Google opens up, and so the music stops. Cancel OK Google and about 5 seconds later the same thing happens over and over again. 

This started happening about 3 weeks ago for my boyfriends phone, and yesterday on mine. We both have Samsung Galaxy S7 Edge phones.

We have turned off the OK Google detection setting in Google and this still happens. 

We have tried using the same cable and listening to downloaded music or youtube in the car and it works fine so it is just Spotify with the issue. 

And no neither of us are saying OK Google!