I had a quest to gain 200 magic dust. My dust manufactury is at level 2. I set it to 9 hrs and a couple of 3 hrs nowhere near the required 200 but the quest completed. This shows I have of gained 123 Magic Dust.
The text is correct at 200 Magic Dust. If the quests completes before that, that would be another bug. We will test that. This report will be archived.