This is strange .............
Started my Edge this morning and it asked me if I wanted to update (Heart Rate) sensor to 3.60 (I think this was the version ???)
I had a bit of time so I selected OK.
It took about a minute and then said restarting sensor.
I selected the check mark as "OK" and started my ride ........................
Sensor did not work the entire ride.
Ran afterwards ................... same result. HR sensor non-functional.
WTF !?
I should mention this is one of the newer Garmin HR sensor with Run metrics capabilities. It has been working fine for months.