Got a possible bug on my alt account. "The Fantastic Banana Ocean Part 6" says get 2 medals in Def Battle 1-3. Have already 3 medalled it in the past. Did the mission and it gave me a 3 medal but the mission is uncleared.

On my main account, I just clicked past it to Part 21 without any need to redo the mission. Might be a typo and it might want map 2-1 (the 6th map which I have done instead?