Had mine for a couple of months and there are a lot of problems with it. Well documented on Garmin’s forums.
The 72bpm issue is the main one for me. It’s what is displayed when it’s starting to read your HR. Not really an issue to be honest, just give it a few seconds to get a reading. It does not constantly read your HR, it does it on demand or every 10 minutes or so in the background.
What is a big problem is that it will drop to 72 whenever you touch the display – or your sleeve does! It does it whenever you get an email/text, whenever you hit a goal or wait for it ….. whenever your wife’s Garmin beeps as it finshes charging! It did that to me on the turbo yesterday morning – I was broadcasting from the wristband to my Edge.
It seems like ANY interruption means the HR resets to the default of 72 and then starts to get a reading again. My Strava graphs look like I died 3 times in an hour on the turbo yesterday!
PS That aside, it’s pretty accurate. Matched against a Wahoo strap it was always within about 5 bpm. The only area it can’t handle is fast changes and recovery – always seems to lag a little