I realised sometimes we can actually trade in dinner set twice in a row During the first completion, the quest is "completed" and I have received rewards, but NPC's quest chat bubble is still there (aka quest in progress). Quest Helper will have the quest still in active as well. And yes, you can still trade in second time. The bug don't always happen, but I have encountered 2 times. I thought I remembered wrong mule's quest completion. Note: Now people out there please don't hate me although I know it feels good to receive up to 2000 NX in a row
Did you encounter this twice on the same character? did you encounter this at 10 or 15 turns as mentioned by Tect?
I just checked today and was on my 16th so yes the previous one was indeed 15th round as said by Tect. It was on different characters. Not a bug then Sorry for the confusion