I'm not certain if it's the same thing or not, but I had my Fenix 3 HR semi-disconnect yesterday. It told me it disconnected on my watch, but the BT icon was still coloured like it was connected and the BT devices on my phone showed it connected. I then went on a jog that evening, and didn't get the audio prompts when my splits changed. Had to keep looking at my watch for the information I like to get during them.
Once I was back and stretching out, I tried force-quitting the app and re-opening. Toggling bluetooth. Eventually only restarting the phone allowed the devices to connect and start syncing again (plus a whole bunch of old queued notifications came through to the watch).
It happens sometimes, sporadically, not enough to worry me. Usually restarting the app or toggling bluetooth reconnects it. Sometimes a phone restart is required. I have no idea if it's the phone manufacturer's fault, Garmin Connect's fault, or the watch.
