Have you also found the OHR completely useless with 18.X/ 19.X/ 20.X?

This is my HR graph, swimming yesterday - suddenly not naturally changed in the middle of the activity (no, I am not a swimming robot ;-) ) My HR graph

The same for me, after last firmware update I have really annoying HR. Yesterday I made 5K training, which usually between 140-145HR, but the Garmin shows mostly 130 HR, and all over the whole training, the HR was far to low. 

But as well for bicycling, Last week I started, and in part of my course (5km flat) with average velocity of 35km/h, the Garmin shows 128HR, which is impossible for me, it must be somewhat in the region of 145-150.    

I feel sad my Garmin wrist watch has been rendered completely useless to me since the latest update. I can't recommend Garmin watches until this issue is fixed. Is it possible to go back to the previous firmware? I did a rowing race yesterday and according to my watch my HR was a casual 120-130 for half the race, only peaking higher right at the end. I can guarantee my HR was around 160-185 the whole time. I would like to add an image here of the graph but can't find the option to do so on the phone.. 

same problems with HR monitor for me since upgrading.  Running race yesterfay and for 3k was very low and then sudden jump to where thought should be.

5k easy run today and simiar behaviour. I've power cycled watch few times and no change. 

@garmin , any sign of fix for the issue?

tks

I think I know how to wear a smartwatch correctly. And there is no suitable solution here. You can email to me to get part of Garmin connect data. I don't want to buy one more chest-strap. Beacuse I think it is not the solution for the problem of the watch.

Same problem here since version 18.22. Heart rate is stuck under 130 and at some point there is a sudden pick to 170.

Upgrading to 18.23 has not fixed anything.

Its obvious that this is a firmware issue, Garmin should have adressed it already,

as they have the data from all the users in the cloud.

I also have the same problem. My measured hr is very low for all my runs. The most obvious is when I run up a set of steps (130 or so) and at the top it says my hr is still around 120. Not a chance. 

Edit: 

To add more context, my Max HR is north of 180. 120 is "very easy". As a consequence, my strava fitness score is dropping considerably, because it thinks all my runs are at an incredibly easy effort. I don't try and take their fitness score too seriously, but like any score or metric it hurts a little to see it going the wrong way :-)

Hello, same issue here, I’m having a FR255 with firmware 18.23 and noticed recently that heart rate doesn’t measure peaks during interval runs (staying mostly around 145 bpm while I used to tackle 170-180). After checking previous records, an interval run on February 13th clearly shows HR peaks. I’m wearing the watch properly (tight, on left arm) and there’s no reason I would have changed in 2 months. It’s obviously a software issue

Same here, this is quite bad. Since at least the last software upgrade either I became amazingly fit (unlikely) or the hear rate monitor does not work properly. I would say 30% lower than what it used to be and then at some point it gets back to more or less normal. Please Garmin fix this ASAP.  Just do it.