The translation pack has the german string in the base pack rather than in the fm subfolder. I will fix it in the mission database.
Edit: Fixed in the mission db
Edit 2: Nope. Not exactly fixed.
It seems that lang files in the mission string folder need to be "complete" because they fully override the core strings.
If I am correct, this was broken in 2.11 when we permitted in-file overrides of core files in missions.
Edit 3:
Still broken in 2.10, rolling back to 2.07
Edit 4:
Still broken in 2.07. Something has gotta be wrong with the translation specific to this mission.
Edit 5:
The core mission XD files don't use the strings so nothing happens if the lang files are in the strings/fm subfolder. Probably means that the translation packs "never worked" for many missions unless impacted players sought out special editions of the missions on Tels' server. What a mess.
Fuzzy recollection time:
I think Tels was trying to push the team to mass convert all missions to move XD data into strings/fm/english.lang but nobody wanted to broach it and even mission authors weren't happy about this way of handling things.
If the translation pack takes precedence, the best way forward is to include the converted XD file into it.
Testing...
Edit 6:
Couldn't get the XD update to work, so I decided to checkout Darkfate's version. It works flawlessly.
I copied their pack into the standard translation pack and the added string files for the other languages worked as well. Darkfate's packs include map files so I'll need to study whether we can avoid that. Otherwise we are basically doubling our mission db or "damaging" our hosted versions to make them translatable. Since this mission is so small and probably will never be edited again we can probably use darkfate's version as-is.