Halfway through today's outing I noticed my Imaging Edge Mobile app wasn't connected to my Sony [RX10]. iOS Settings > Bluetooth also showed the camera as Not Connected.I'll be doing more extensive field testing tomorrow on a hike.
The camera Bluetooth was turned on. No amount of fussing with the app made it connect.
I turned off "control with app" on the camera and clicked connect in iOS Bluetooth. The camera connected but still took about a minute before the app location service connected.
I'm not sure if it was the "control with app" feature that prevented the location Bluetooth function from working (probably), or if it just didn't like the ~12 hours since the last connection.