P.S.A.: Destiny 2’s Ketchcrash Activity is not to be missed
Ketchcrash is a brand new activity that debuted in destiny 2 Season of Plunder. You’ll move through various stations until you reach a huge pirate ship. This is the main theme of the season. Some players have experienced a Destiny2 Ketchcrash bug, which prevents them from obtaining the rewards or progressing through the quests (mainly Ahoy or Aweigh). We might be able to help you if you are one of these players.
First, ensure that you have at least one piece of seasonal armour. This is a solution that has been suggested a few times. If I recall correctly, I used the armour pieces from the Gift of the Thunder Gods box in the H.E.L.M. space. You should see if it helps you.
Another option is to remain in the quest until the timer expires, rather than leaving the activity and returning to orbit or another place. Others had reported that restarting their game worked, as did pulling out the Ghost and keeping it there when they opened the chest. Bungie also suggested this solution and advised people to wait until Scoreboard appeared.
Bungie appears to be investigating the issue. It could also be a problem with general delays in reward drop drops. Another tweet suggests that another issue could be affecting quest progression. I hope any of these workarounds will help to fix the Destiny2Ketchcrash bug.