In order to get the video, I had to click the link labeled "Video" below the image of the
product. Clicking that link caused VDH to recognize the content on the page without
actually launching playback of the video. This might be because I'm in the US & the site
is the Italy branch of the organization. It was a minor inconvenience.
In any case, I ran ffprobe on the master manifests I found in the VDH Hit Details. In
both cases, we have audio tracks shared by multiple video tracks. This triggers a known
bug in VDH. It can't figure out how to correctly interpret a master manifest in which
the same audio track is paired multiple times with different video tracks.
If you want to avoid having to download separate audio & video tracks then merge them,
you can do either of 2 things. You can simply leave the 2 tracks separate & play them
using the VLC synchronous playback feature. Or you can learn how to use ffmpeg,
something I'm sure you've come across in your searches of this forum. If you continue to
use VDH, you will continue to have to do separate downloads. If you learn how to use
ffmpeg instead of VDH, then you will be able to do just a single download, & the video &
audio will already be combined into a single file.
It's up to you. You might find this link helpful for learning about the various things
you will need:
https://groups.google.com/g/video-downloadhelper-q-and-a/c/BzPLK2YyL-s