Since the update to SW version 19.18 the pulse rate values have became quite inaccurate (usually higher than expected) and the HRV measurement during sleeping got very infrequent, almost no values at all.
Since the update to SW version 19.18 the pulse rate values have became quite inaccurate (usually higher than expected) and the HRV measurement during sleeping got very infrequent, almost no values at all.
Good news!
After restarting the watch, both the inaccurate pulse rate and HRV issues seem to be solved. Last night the HRV registration was perfect, as it formerly used to be. So, finally I got completely…
Same as this user too then 955 HRV data not being recorded - Forerunner 955 Series - Running/Multisport - Garmin Forums.
Not ideal, but since not everyone is experiencing the same issue I would try a soft…
Good news!
After restarting the watch, both the inaccurate pulse rate and HRV issues seem to be solved. Last night the HRV registration was perfect, as it formerly used to be. So, finally I got completely calmed down. 
Lesson to learn: sometimes (let's say once a week) soft reset of the watch makes sense and can solve some problems, which is even more advised after SW update. By the way, it is strongly recommended in case of smartphones, too.
Did anyone face this issue as well with Garmin series? I have a Fenix 7S Pro SS and having issues lately with the measurements: it depends of the day, but always min gaps or lot of.
Yesterday:
the day before
in the watch itself there are no gaps, but because I think the way the format of the graph is in the fenix 7s pro ss, since it just continuous the line where the gaps are.
Does anyone know how to fix it? I don't have any gaps in HR measurements during the day or night.