I wrote to Garmin support two weeks ago - unfortunately they didn't respond.
I have two separate issues with the Ski app on the Descent MK1: 1. The auto-lap feature is completely wrong - it shows that I made 2 to 3 times more runs than I really made (f.ex I made 10 runs and the Activity shows 30 shorter ones). I rarely stop during a run and I ski down the slope in one go - so it's strange that it gets confused like that. I also catch the watch registering a run while I'm on the lift and going up. This is the primary function I use for skiing and it's irritating that it's not working properly. 2. I get unrealistically high speeds - more than 100km/h, sometimes even 200 or 300 km/h are displayed as top speeds in my activity. In reality I rarely go over 60-70 km/h. I tried with 3D Speed On and Off - there is no difference Both of these issues were not present on my previous Fenix 3 (non-HR) watch, that was used in the same way on the same ski resorts, pistes and lifts.