Heart rate data whilst running seems off?

Most times it shows pretty much correct heart rate from start to end while I run, but your example has happened to me too now and then over the years, with different watches and firmwares. In most cases it has been because the sensor got locked onto the cadence. 

I had the same issue on every run since the update. HR never climbs above 150. I was sent a replacement watch and it’s still happening. It must be a software issue.

I'm wondering, does it only happen with running?  What if you do something like walking up stairs or hills?  Or something with totally different movements like lifting weights or cycling?

My hilly walk from yesterday seems to have a normal HR recording which peaks around 165 and seems to echo the elevation profile. But each section ramps up steadily for many minutes, not sudden spikes and of course I'm not bouncing my wrist like with running...

I haven’t tracked my HR during a walk, but looking back at the time I did one yesterday there was just a small spike to around 90.

I did a 17 mile hilly run Sunday at a decent pace and it never climbed above 155 (slightly higher than the 150 I mentioned above). My watch is worn the same way every time and I was not wearing any sleeves. This started happening after the software update.

I haven't been on one of my very steep hikes lately, so can't confirm whether it still tracks as well as before the upgrade. E.g. all the way to my max HR in about 5 minutes...

Yes it seems to only do this with running. When I am out walking it seems accurate and when I run upstairs it spikes quickly and then goes back down as normal. When I did a weights session it was going up to about 135 and then down to about 90 to 105 in between sets. I think this was pretty much correct, so its just this strange running delay. I'm going for another run later so I will see what happens.

This is from a treadmill run today, using only the watch sensors. This is a demanding activity to track, since the pace and heart rate changes a lot. The watch does a very good job, and it seems very responsive. 
During the walking the first 15 minutes, I ramped the incline up and down, which shows well at the heart rate, but the watch does not know about the incline, so the power is not affected.

same problem with floor climbing. The HR tracking is not reliable ever since i gotten the watch.

For running, HR were good on the older FW.

Nice graph. What exercise was it? For a vo2max intervals too low hr, for a LT to short intervals.. Can you trust, that on  380W (is it from the watch itself? Seems to be very steady heh-heh) you have hr only below 160? Have you compared the last results to the old comparable one? 

I can't trust the OHR at all after 18.xx - that is the biggest problem for me. So i must wear an external hrm every time i do intervals.