Hi Gregory MOW,
Thanks for reaching out in Apple Support Communities. If we understand correctly when you're connected to a Bluesound Node 2i via AirPlay and you open a browser, the iTunes app will launch automatically and start playing the first song in the library. We see this behavior continues despite testing with different browsers and if you quit iTunes. We can see why you'd reach out about this; we'd like to help. We'd suggest starting with the steps below to isolate the behavior:
Start your Mac in safe mode: How to use safe mode on your Mac. After the Mac completes starting up in safe mode, restart normally and test for the behavior.
If the behavior continues after starting in safe mode, test again for the issue in a new user account: How to test an issue in another user account on your Mac
Let us know what you find.
Best Regards.