Hey @Mickeyg83irl, it's working as designed. With Nest devices, the main account owner's music and library is available to all. Under license agreements you're only allowed to listen to one instance at a time with a single account. If another activates, your account on another device the music or movie stops.
To prevent this, you will need to subscribe to a family music account that allows multiple users, and each user will need to set up their accounts to use the devices simultaneously with different music in different locations. Hope this helps and let us know if you have other questions.
