Thanks to all who are sending info into Apple on this. I love these AirPods, but the connectivity issue with my iPhone 6S is disappointing. I hope it's just a software issue, and not a problem with the Bluetooth chipset in the phone and/or Apple Watch.
Took a six mile hike yesterday, and decided to listen to some downloaded Apple Music on the AirPods. As expected, I started having issues not even a half mile in - my music kept inexplicably pausing all by itself. I checked to make sure the phone was waking up and somehow hitting pause buttons. I tried turning off Automatic Ear Detection on the AirPods. Nothing helped until I disabled cellular (T-Mobile) by using Airplane mode and then re-enabling Bluetooth and WiFi. Interestingly, the iOS reported it couldn't put my watch into Airplane mode... turned out my AirPods had jumped ship to the Watch. Eventually I got it sorted out and was able to enjoy some contemplative music on my wanderings with only a couple incidents of uncommanded pauses.
This morning, listening to more downloaded music, this time with cellular enabled but at home on WiFi. Just the occasional left-right burble, and then about 15 minutes in, the music paused. I looked at my watch (original 38mm Sport), and it was displaying the red "No Connection" icon at the top. Swiped up to see the AirPlay icon was Blue; tapped on that and saw my AirPods had jumped ship again to my Watch. After a few seconds, the watch reconnected to my iPhone, which was sitting right in front of me (I was reading web forum in Safari), the AirPods then reconnected on their own to the phone, and the music remained in a paused state. This is probably what was happening on my hike yesterday. Also happens when listening to Podcasts.
I was able to have an hour-long FaceTime Audio call today by using only one AirPod. If I use both, chances are they'll disconnect from the phone randomly switching all audio to the handset, and I have to re-select them as audio source (or wait long enough and they might resume on their own).
I'm starting to think both are related to the AirPods jumping ship (i.e. via continuity) to my Watch. What's weird is it still happens even with my watch powered off (but not un-paired). Hesitant to un-pair my watch as it means I'll have to re-enter my ApplePay cards again.
So, there's a huge hint. I'll see if I can report this to Apple.