I STILL cannot open this chest. I continue to get an error "You may only have one of a unique item" appearing when I do not have any unique items in my inventory OR bank slots.
Initially I attempted to shift the Loomweave armour enhancement from some old armor to some new and I had this problem when trying to remove the item from the armor.
So I destroyed Loomweave armour enhancement and got the Knight of Feywild Supplies pack back from the rewards vendor but continue to get this error even AFTER this problem was meant to have been patched.
I have reported this using the online help, received one reply asking for more information....... expanded a little and since have had not response.