Quest Completion Bug

ISP:
Telstra

Type of Internet Connection:
Cable

Internet Connection Speed:
24Mbps

Date & Time:
9:30PM (GMT+10)

Frequency:
Once (Did not reproduce)


Character Name:
Janna Windforce

Race:
Miqo'te F

World:
Tiamat (JP)

Class/Level:
Level 13 Conjurer

Area and Coordinates:
The Black Shroud, Central Shroud
X:20 Y:28

Party or Solo:
Solo

NPC Name:
Balarr

Monster Name:
Diremite


Steps:
I had just finished completing the objective for the quest "If Ye Break Faith", and was running back to Balarr to hand in the quest. There are a few Level 12 Diremite spawns right behind the shack he is located in, and I pulled aggression from them running towards it. I thought I would be able to quickly hand in the quest before the Diremite hit me, so I tried to do that, but just as I hit the complete button, the Diremite hit me. The chat box printed '"If Ye Break Faith" complete!' and I received 211 Gil for completing it. However, I received no experience for handing in the quest, and it remained in my journal. I was able to hand the quest in again, gaining another 211 Gil and receiving the 2625 experience.

I have taken a screenshot of the chat box showing the quest being completed twice, and uploaded them to Imgur.
http://i.imgur.com/AjrYQAF.jpg