Garmin Connect keeps forgetting Forerunner 935

Far too often, when I open Garmin Connect, I am greeted by a message saying "Device Not Connected: It looks like your Forerunner 935 device isn't fully connected ..."

I then have to put the device in pairing mode, and reconnect it in Garmin Connect. Most of the time I get an email saying "Thanks for registering your Forerunner 935". I now have six such emails since September 4.

Needless to say this is incredibly annoying. Does anybody know what's causing this?

This is not happening to my other Garmin devices, only the Forerunner.