Dropped items and not being able to Need the item

So this has happened to me twice now, and I'm not sure if it's a bug or not, but when I go into a dungeon and there is an item that is dropped, I can't need it. I don't have the item at all, and yet it wont let me Need it. For instance, I was recently in a Stone Vigil dungeon with my lvl 40 PLD, and Aetherial Mythril Barbut, a helm, dropped, but it wouldn't let me Need it, it was grayed out for some reason. I don't know if its a bug, or what, but its very odd and irritating when I need to upgrade a class.

That one looks pretty tank-y but it's a DRG piece :) on some of those you can't roll need. Not a bug

But then why doesn't they change the peice requirements to only DRG? instead of putting both tank, and dps specifically on the item?

Its DESIGNED for DRG - tanks can wear the pieces but not roll need afaik. Like mage gear which can be worn by all classes (the lower level drops I mean) but only magic classes are able to roll need

Adding to the above, the equivalent tank helmet piece for that dungeon is the Aetherial Mythril Celata. If you compare the two you'll notice that they have difference defence stats and as a tank, you really don't want to be wearing the dragoon gear (or DPS gear in general even though often it lets you).

Aetherial Mythril Barbut: http://na.finalfantasyxiv.com/lodest...m/a3e16d9c760/ (Defence 53, Magic Defence 39)
Aetherial Mythril Celata: http://na.finalfantasyxiv.com/lodest...m/0a96c03aaa1/ (Defence 73, Magic Defence 73)