mine doesn't work, I've already donated a lot to a lot of different giants, and it's stuck at zero, I've spent +110 favor points once (after I got the quest)
It looks like you haven't donated enough favor for quest credit yet. You have to get 23 favor with a giant before it clicks off credit, and you have to have done it since you started the quest. Your highest so far is about 11, so keep at it and you should start seeing credit soon!