Una's Task 'Rest Bonus' not working at all?

[Skrewed]

I’ve never done any Una’s Tasks since I’ve started playing/unlocked the mechanic.

My Rest Bonus was at 100% (full green bar). I started today taking a bunch of Una’s Tasks, tackling one by one. After 6 quests, I’ve seen that I can’t deliver anymore.

I still have 40 Rest Bonus, as you can see on the Screenshot:

But on the bottom of the window it says: “0 available” and when I try to deliver a quest that is done, I get this message:

What is the point of the Rest Bonus if you can’t fully use it?

[Saturn]

Una’s rest bonus does NOT let you do MORE Una’s tasks, it gives you DOUBLE rewards for the 3 dailies that you completed.