Working on Vision - Warden Amala question

Hi there, I just started working on Vision (yeah, I know i'm late to the party) and I figured i'd start with Istan. I've managed to finish everything in the Visions of Istan collection except the Warden Amala kill. I'm not sure what i'm doing wrong and could use some advice.

I bought a memory essence thingie from the NPC at the docks and I have it in my inventory. i've killed the Warden 4 times now over the past week and this collection item hasn't triggered yet. I still have the Memory Essence thing in my inventory and I'm sure I've gotten credit for the event because i've gotten the loot from the event. Am i missing a step? Any ideas?

Has anyone else had this problem or know a solution? I'm having the exact same issue. I've gotten other visions achieves just fine and this is the last thing I need for the istan one, but for some reason it won't trigger. I've finished the event on different characters and submitted a bug report with no luck, as they just say they cant credit me for an achievement. Any solutions?

I would post this in the bugs forum. You may get a somewhat different set of players reading that one, and perhaps more help.