Achievement : Mark The Desert: A

Hi, the template didnt seemed to give any valuable informations on my bug.

The achievement : Mark The Desert: A is actually bugged in my case.
I've killed over 10 A rank hunts in Thanalan yet it is blocked at 4/5. I've tried to kill some more just to make sure I wasn't going crazy but after killing Zanig'oh and Dalvag, it's still blocked at 4/5.
I did received full participation on these hunts.

You need to kill every A-rank hunt mark in Thanalan at least once each. That is what the "unique" in the requirement means. Killing the same one multiple times doesn't count.