For real, this one is really bizarre.
You have a list to select ships, you make it so it has a scroll function, but you limit the list to 8 ships!
Take the mission battle of valcour, you can only have 60 point ships, what if you have 8+ bigger ships?
Affilicated bug. Select some ships so the list gets filled back up to 8, then unselect ships from the mission => ui bug.
Do you test?