the watch was working ok before, but since the update to v8, there is a huge hysteresis in the altimeter. In other words, when climbing the fenix is approx. 500m late. During the jump, the altimeter does not move too much, and once on the ground, the altimeter dysplays decreasing values from around 2300m to zero, this takes several minutes. Also impossible to calibrate during the climb.
i contacted garmin support but if someone has an old firmware or a trick that would be great.