Can I loot the same item multiple times in raid finder?
Solution 1:
Yes you can, it's perfectly possible that you can win the roll and receive the item, and then use an Elder Charm of Good Fortune and receive the same item again. The 'Bonus Loot' system does not check if you already have the item, only that it is relevant to your currently active spec.
In addition, the loot system in general doesn't check what gear you have, it only checks the gear that is relevant to you, meaning that even without the use of Elder Charms, you could get the same item from the boss every time you are eligible to loot it.