Achievement bug

[FireHands]

Time: 9:48PM on 26/3/2016
Frequency: N/A
My world name: Odin
His world name: Zodiark
My character name: Fire Hands
His character name: Astral Dee
Monster name: Ravana
Class/Level: Scholar/60
Party or solo: Party
In-game time: 9:48PM on 26/3/2016
Area and coordinates: Ravana

What happened?
Simple, we went into trial roulette and at the very end 'Astral Dee' somehow unlocked three achievements that in no way could be obtained in just completing the trial roulette instance.

'Astral Dee' unlocked 'To The Dungeons IV', 'To The Dungeons V' and To The Dungeons VI' sequentially at the end of our Ravana trial instance.

How is this even possible?

I attached an image as proof.




Link to original image (bigger/clearer): http://i.imgur.com/FS83w1Z.jpg