Hi all!
We fixed a bug today whereby you could get "treasure collector" achievements from someone else's pet.
Unfortunately, we have no way to tell who deserves the achievements and who got them just by visiting another pet's treasure chest.
So, what we've done is revoked all awards of that achievement (sorry!) If you do deserve the achievement, it should be a simple matter to re-qualify for it.
Again, sorry, this was the most straightforward way of rectifying the problem!
-Alex
Edit:
If you received the pirate map twice (once for the first time you got this achievement, and a second time when you had to re-earn it) then you are welcome to keep it. If you have already deleted yours, we are very sorry, but we cannot give you a new one.