No elevation or altitude is recorded in the FIT file for the activity, the Fenix6 knows it is an indoor ride and while some gear can fake grade changes by raising and lowering the front wheel I do not have such expensive equipment.
So a wild guess is the barometer is sensing air pressure changes from the nearby fan?
Oddly only near the end of the ride, every time.
It also seems to spike up and then down equally, like the watch knows it's wrong or is settling.
Unfortunately there is no way to record the barometer during an activity as a sensor, I've long wished for that option, along with the magnetic compass as an activity sensor.
I am also using a HRM-PRO-Plus which during running can sense grade changes but those metrics are not turned on by the watch during a ride?
I don't see how the datafield developer could fix this if the watch API is sending bad data, other than an option for disabling grade changes for an indoor ride.
https://i.imgur.com/URAF2vA.png
