Hi
I've had the my Fenix 5 since june. Upgraded from a Fenix 3 non-HR.
When I first got it, I experienced quite a lot of elevation drift while not moving (upwards of 50-100m in a few hours) - an issue I didn't have with my F3.
However, it got updated quickly and seemed to fix the issue, and only drifted a few meters during an entire day at work.
Now, since 5.40, it's back to drifting - and just today, it drifted 40m during the night, while laying on my bedside table.
A few times it's even bumped my elevation from 200 to 900 m within minutes.
I can't seem to find anyone else with a similar issue - so I'm asking here, as I'm getting tired of having to check and calibrate the altimeter several times a day to stay within reasonable elevations.