The main reason I upgraded to the IOS 11 public beta was so that I could change the behavior of double tapping my AirPods - I have been waiting for that feature since I got my AirPods many months ago. I wanted the right to skip tracks and the left to play/pause. For the most part that has been working great, even on my MacBook and non IOS devices like my PC. What I have noticed though is that sometimes I get very unexpected behavior on my MacBook. If I listen to songs on Spotify it starts working as expected, but then if I watch a video on Youtube and then go back to Spotify it wants to control my Youtube audio...I have to close out of Youtube. And just now I had a situation where I was listening to music then went to Facebook and sent a message then after that every time I double tapped it gave me the Facebook message sent sound...it didn't send a message, it just made the sound. And even worse when I closed out of Facebook it continued to make the sound. I had to put my MacBook to sleep then wake it up for the controls to work in Spotify again. Very strange. Not sure if this is a MacBook thing or an AirPods thing. Hopefully this will be fixed in a future firmware update.