Apple Watch 3 stop counting climbed flights

Hello,

I have an AW Nike+ edition s3 since 2017.

Exactly 3 years after first use, it stop counting the flights I climb.

Since october 20 this year, it has no flight climbed at all. My iPhone got datas.

I didn't change anything this date. The watch run watchos 6 this time.

Also, as it couldn't update to watchos 7, I reset my watch last week (unpair - pair) and update it, because since iOS 14 the maps of my workout gone (https://discussions.apple.com/thread/251801586).

It didn't change anything.

I checked every parameters in the watch and the iPhone (Settings, Privacy, Fitness Tracking and Health enabled etc.). No success.

I can't believe that's a coincidence that my first datas from the watch are dated as of october 20, 2017, and the very last as of october 19 2017...

I tried to attach here 2 screens of the very end and start of the AW data source of "climbed Flights" in Health App, but seems to be forbidden....

Is anybody has the same issue ?

thank you, have a nice day.

Cedric