We seem to have people asking this every weekend :/ Unfortunately, even when a quest is a weekend quest there's still an element of luck to it, so some weekends you might just be really unlucky.

With Maleria, she gives rewards based on the rarities of what she asks for, so you may have gotten unlucky with an expensive low-rarity item. I know there is at least one weapon she asks for that is rarity 1 and thus always gives terrible rewards for it. In any case, yes, the weekend quests are working correctly. Sometimes a quest isn't profitable and it sucks but it's part of the game. /shrug