Mediaviewer selects the static part of the description as caption when the changing part is the relevant. Problem exists with all languages and all WLM photos.
Example:
Current result for finnish :
"Tämä on kuva suomalaisesta monumentista, jonka tunniste on"
Expected result for finnish:
"Katedralskolanin liikuntasalin peruskorjauksessa löytyneet rauniot"