20.26 heart rate accuracy

I don’t think the broken optical HR is new. There have been threads reporting whacky HR (under-reading for long periods, during intervals) since 18.xx firmware. Definitely need a 3rd party sensor if you want good HR data. I agree it sucks given the price 

I’ve seen the Coros armband. How do you find it? I use the H10 strap here personally and find it great but was considering an optical arm strap at one stage

I really like the Coros. It just plain works as advertised. I've had it for a couple of months and I've done testing between it and my 955 and until this last update they were within a couple bpm of each other. 

rundad86 said:

I don’t think the broken optical HR is new.

No it isn't.

I will have to reanimate the thread for it. Unfortunately, for me it keeps on having uge jumps (underestimating at first, then suddenly jumping up 50 beats or so) when I use the optical HRM during commuting with a bike.
Does not impact me too much, as for training I always use external HRM straps and for walking and hiking the values seem to be ok, but still it is an error and for me it is still not fixed.

I solved this issue reseting to defaults the watch,

Sounds interesting.

Can you explain exactly, which steps you did?
I would not mind resetting watch and acitivity settings once, but I would hate to do a full factory reset and lose data for HRV and things alike.