Re: QC35 Series II - Controlling one device plays and pauses audio from other device
suprised you have not received a response from Bose yet. What they would tell you which I think is a great first step is start all over again from scratch. Get rid of all the bluetooth connections and devices on your phone and Mac and then factory reset your phone and start connecting again.
If you continue to have the problem, then from my readings here of other posts, it could be an issue with your MAC OS. I am a windows user and have tried my ip 7+ with both my desktop and laptop (separately) and the audio switching occurs as expected - no issues.
Another thing to eliminate is the browser. See if you have the same issue with say Safari instead of Chrome. Also check to see if it is a streaming issue by playing a local resident MP3 (no internet) with a local player app (not browser). If it is MAC OS issue, the results should be the same.