Treasure bags are empty.

[Mofus]

Anyone else picking up treasure bags and not getting any thing? Ran a bunch of level 14 quests with a guildie, and neither of us was getting any thing in the treasure bags.

[Matuse]

In certain quests, the original area designer forgot to hook up the drops to the collectible drop table, so you see bags but they can't be looted.

[Alrik_Fassbauer]

Some Feywild bags are indeed still empty.
Some could be fixed now, because I vaguely remember patch/release notes saying so a few months or weeks ago ...