On my last run activity on 10 Nov the hear rate looks broken:
The Training Effect is only 1,3 Some Benefit. For this longer and more intensive activity it's just not correct, usually I have 4,5 or 5 for similar runs.
All previous activities were always ok, short and long, the last activity with normal heart rate was on 7 Nov.
I wear the watch directly on my skin (wrist).