Mediainfo only parses the furthest down tag layer when they use the same name. Matroska stores them both and they have different meanings. The higher the "TargetTypeValue" it is the more generic of a tag it is compared to the lower number option. In this example the "70" one is for the show "Lost", while the "50" one is for the specific episode, the pilot. Mediainfo only shows the episode one.
Mediainfo only parses the furthest down tag layer when they use the same name. Matroska stores them both and they have different meanings. The higher the "TargetTypeValue" it is the more generic of a tag it is compared to the lower number option. In this example the "70" one is for the show "Lost", while the "50" one is for the specific episode, the pilot. Mediainfo only shows the episode one.
If you open the file in a hex editor and look at the tags that way you'll see they are both there.
Edit: The issue is present in all output modes tested, including xml and the full text.