Ive just done 15 quests for him and got 0 amulets, that never happens to me, it wasnt until I got to the 7th quest that I saw more than about 60k sp, I did get 2/3 items for some quests, but it was mostly cheap items. Im not sure what extra you're supposed to get from him? said the same on the news page.

Quentin's weekend quests give about 2 items as a reward, usually one of the usual items and one restockable item. You're not guaranteed to get more amulets from them being the weekend quest, I only got 2 amulets today myself. I did get more sP than usual though, around 100k for a few of them but usually at least 50k or so.

Normally Quentin doesn't give out a whole lot of sP, so even 60k is kind of a lot for them.