How come nobody has said anything here? It is just trying to take a still photo (no live photo) and music stops whenever I open the camera app. This is the biggest dealbreaker on the iphone 6s. I think I'm returning if they don't fix this soon.
It's been like this since iPhone 1.0. Keep waiting. It will never happen. It's done on purpose.
It was fixed in the 9.1 beta 2, but it reverted back to this behavior in the third beta - at least now it resumes playing immediately after exiting photos.
I also assume it's related to the live photos, but it's incredibly annoying that this happens even when they're turned off. I'd express your annoyance about this to Apple too - I'm definitely unhappy about this as well.