I suddenly had this issues the my activity didn't upload to the Garmin connect app. Not automatic or manually. The device (Edge 530) wasn't connecting to my phone.
For some reason unknown to my during my commute to work the connection stopped working.
I tried all the steps suggested by Garmin and the kind people on the forums steps to try to reconnect with it, all in vain.
One thing i noticed is when after resetting the device and re-installing the Garmin connect app is that in my Phone's Bluetooth connection page there is like 10 (BLE) edge devices and there is more keep coming in the available devices list. this is giving me the impression that the edge 530 is broadcasting like multiple signals or the Bluetooth hardware is turning off and turning on and creating a new available device.
Any one else have experience this before? I'm getting really disappointed in this device, i have been taking extra care of it and for it to malfunction like this.