Hi there,
since ver. 6 it seems my altimeter is totally off. I am currently at home, less than 50m above sea level and the Garmin watch tells me I am at -700m.
I have tried to recalibrate it via GPS, I even looked up the air pressure to adjust the height. It works for a short time, then it goes back to the whack reading.
It seems to do fine with altitude changes (as far as I can tell) but the height readings themselves are totally off.