Benedict's Chest Bug

[ortholomus]

When you kill Lieutenant Benedict in Durotar, and he drops Benedict's key, when you go to open to chest at the top of Tiragarde keep, the chest does not contain the item [Aged Envelope] -- in fact it's entirely empty. What happens is you unlock the chest, it shows as empty, then it says "interrupted" and a Marine spawns and attacks you.

First off, no, I do not currently have the question item, and I have checked that I have the key in my bag, and have replaced the key multiple times and the issue persists. Also, I do not have the quest currently that the [Aged Envelope] brings.

I have noticed and heard of many other people having this issue.

[Nacht]

happens when someone picked up the letter a short time before you. the chest doesn't disappear so it's a bit confusing