I Have the same issue, let me provide more information.
- This issue occurs with both my iPad Pro and iPhone 6s when they are paired with the qc35 for long. Both have the latest iOS, and the latest Bose Connect App.
- My Bose QC35 were working perfectly for months, since I purchased them earlier this summer. But, sometime over the last 30 days or so, unexpectedly, I noticed that although I could see the QC35 paired in the Bluetooth settings, I could no longer see the qc35 in the list of speakers when playing a video or music.
- i did many things, including deleting the list of paired devices and repairing the qc35 with my iPad, this allows the qc35 to work well for a few minutes, while I watch a movie. Using Bose connect App does not fix this issue, it will reconnect the qc35 to the Bluetooth by reactivating the link if needed, but, it is not able to restore the qc35 to the list of speakers in the menu when watching a movie. As soon as I pause or stop the movie, the qc35 remains in the Bluetooth list of paired devices, but disappears from the pull up menu list of audio outputs (that menu bar we get when using our finger from the bottom up).
- We have an intermittent problem here, whereby the Bluetooth pairing is working, the qc35 even acknowledges it is paired, but it can not be used reliably for long.
The issue is deep under the hood. As it is right now, the qc35 has become a brick. I hope one of the Apple Bose gurus can shed some light.