The quest is simply asking to complete any "mission" with a difficulty of 5 or more, I did Storm Recovery Level 10 and does not count it, so I'm not sure why BB suddenly decided to come with something weird and call it a "mission", it does not make sense at all, I thought they name it as a mission to make it short as any Scenario, Adventure or Venture!
https://i.imgur.com/KUQKecu.png
Seriously? what does that mean?
I think it is Adventure, isn't? why you hate to make things easy to understand for players?