Starting yesterday morning, my altimeter started acting up. When I woke up, it was showing -5678 meters. After a GPS calibration to the real altitude, it started not showing hourly altitude. After that, it started to act up with the watch faces. I've uninstalled the one I had and used since day one without any problem and installed Actiface, knowing that this watch face never gave me problems. After the installation and a restart of the watch, only the default watch face was available for use on the watch. I've installed another one, did an GPS altimeter calibration again, it worked fine even after a restart, but only for a couple of hours.
Now, again, the altimeter doesn't show anything.
I did 2 soft resets, pushing the Light button until the watch stoped but still the same problems with the altimeter but now the watch face works just fine.