I loaded this GPX track into QMapShack 1.6.0:
I added and activated the DEM files from viewfinderpanorama.org and "wrapped" them in a vrt file. The DEM files are loaded and the hillshade is generated just fine.
Still, if I click the track, an info message appears showing a total uphill of more than 4000mt for the track, which is not the case (I am sure of that).
I am wondering if the matter is only aesthetics and if it's showing the elevation in feet rather than meters or if it's just a coincidence.
Hope this helps somewhat.