I almost put this in the pinned duplication glitch topic, but it seemed to be talking about a different kind of duplication glitch, so I decided to make a separate topic.

I was defeated by the Crinch the first time I attempted the quest. I came back a while later to try again, but when I did I had to do the same things again. This, on its own, would not be an issue. This seems to be how certain quests or parts of quests are coded - if you get defeated or run from a battle, you'll have to repeat the actions to get to the fight.
However, this is the first of those quests that the part that is repeated gives you an item, and therein lies the problem.
I was only able to submit one of the Crinch's presents, so now I have a unexportable item taking a permanent slot in my Adventure inventory.

(The Pixpet in question is my Oecko, Benthazar. I've noticed that sometimes staff members ask for that when fixing item-based bugs.)

Thank you for your time!

EDIT: On the request of Moderator BK47, I've written down a bug report. It's below.

Description of the Bug:
Duplication of a quest item in Adventure.

Steps to reproduce:
1) Start the Crinch questline by talking to a Pixpet called Timmy. I think he's found in the Pixpet Garden in Pixpet City by exploring.
2) Go to Golden Dew Mountains to do the quest.
3) Do the quest as normal, until you get to the fight with the Crinch. I can't remember if I lost or if I fled from this fight, but I definitely did one of the two.
4) Return to do the quest once strong enough to defeat the Crinch. At this point, you should already have the Present for the Crinch in your inventory. You'll have to repeat the conversation with Klaus, and with it, obtain a second Present for the Crinch.

What should have happened?
I should have obtained only one Present for the Crinch.

What did happen?
I obtained two of Present for the Crinch, and could only submit one. So now I have a leftover Present for the Crinch taking up one of Benthazar's inventory spaces, and no way of removing it.

Name of pet affected:
Benthazar

Where/When did it happen?(Location/During Battle...)
Golden Dew Mountains, during the Crinch questline.

Block ID (if applicable):
Not sure; I don't know how to check.

@BK47 I've done the bug report! It's in the original post.