altitude

today I went on a trip with totally crazy altitude difference. 800 Hm too much displayed. i know the track, only light waves. Sometimes values between 30% and with a 96% slope are displayed, in real terms maybe 2%. It's just ridiculous that Hammerhead can't get a handle on the problem. But the problem has only been felt since the last map update at the end of last year. I now have 3 devices. Everyone has the same mistake. This was not the case a year ago, my Karoo even showed too little altitude difference compared to a Garmin Edge 1030.