I've downloaded a course via three different methods to my Garmin Edge Explore 2. Oddly, each method produces a different elevation gain. I'm curious why the error is so large.
Here are the three methods and accompanying screenshots:
1. I took a gpx trail from Map My Tracks and uploaded it to Garmin Connect on iOS. This then synced with my Garmin device. 615m ascent.
2. I uploaded the same gpx file to Komoot, which auto-pushed the course to Garmin Connect. This was downloaded automatically to my Garmin device. 538m ascent.
3. I used Komoot's Connect IQ app to download the same route I had uploaded to Komoot in step 2. This time, even the climbs have changed! 574m ascent.
What causes this disparity and what number should I trust?