Bug report: HR spiking when stopping at a red light

My issue seems to be the opposite.  I have spikes, the thread you linked is about drops. Maybe Garmin-Sierra can advise on this?

Take a look at that other thread again. The main post shows drops in heart rate, but others, including myself, see other heart rate inaccuracies and are documenting in that thread. I see a steady increase far above actual heart rate, followed by a sudden drop toward the more likely heart rate. I experience it only once at the beginning of a run, but in many ways it looks similar to when you stop running. We might actually be seeing similar things in the sense that we might be seeing heart rate spikes as we are warming-up (or re-warming-up in your case). I suggest documenting this in the other thread as the other thread has Garmin-Sierra's attention.

Yeah you're probably right.  I'm gonna move over to that thread, thanks.

O! Sorry, I wasn't paying enough attention. So it has nothing to do with fr955. 

I'm not a doctor, but it looks like an Exercise Associated Collapse (EAC) And I would recommend discussing this with a sports doctor. And of course I can be wrong :)

That's interesting, I'm gonna look into it.

My issue is none of that was happening on my old Forerunner 645, but I'm going to keep an open mind and look it up.

It may be that the old OHR wasn't sensitive enough to see that. But the chest strap should show it without any problems. This is normal behavior of your body, but not very healthy. 

I looked it up and it doesn't seem to be the issue.  EAC is the complete collapse after a long and intense exercise, like a race.  In my case, the HR spikes even happen during my slow runs, which I run around 6:30 min/km pace.

This one is from 2 weeks ago, it shows 3 different stops pretty clearly.  The 2nd stop around 30 min in the run shows my HR spiking from 143 to 160 and then dropping down to 136 over a 14 seconds stop.  My expectations would be a regular lowering of my HR from 143 to 136 instead of that spike.