Mission 78 - no text!

So I’m running this hardcore horde playthrough and i actually got myself a friendly NPC teammate. Only problem - he had a mission for me. A mission that was never coded. Mission 78.

What do I do now? I already accepted it. Will it disappear after a while if I just keep saying “sorry, not yet”?
Whats the objective anyway? Could I edit the savegame to make it into a different mission or would that bug out the game?