Hello so I completed the Fool's Gold quest for the first time on a new character and then immediately completed it again for half the experience. After 24 hours I tried to repeat it, but everytime I click on the quest icon (lightbulb) above Lita Lawless the normal text window opens, but so does a "Quest has ended due to unknown error" or something like that that prevents me from completing the quest.
If you wait another day or two then you will be able to complete the quest again. The quest cool down is simply longer than it appears. This occurs with every single repeatable quest that I've done so far. I do not know if this is intended or not.