This is my second day wearing a newly purchased Race S.
Same issue, unfortunately.
As I sit here and type, the heart rate reading is 88.
There is no way this can be real, as my usual range is somewhere between 55 to 68.
This afternoon, I also tested exercise, and the HR monitor reading was all over the place; before I warmed up, it showed 120+, while my Apple watch read 60-70, and in the middle of exercise, it stopped getting my HR. The green light was blinking; however, it was in exercise mode.
I tried removing and re-attaching, resetting, and the trick of toggling on/off 24/7 monitoring; I really wanted to love this watch, but now I am in doubt.
I hope this is a bug that can be fixed by update. I will give it another week and decide if this is a return as well.