Hey guys!
What you described is how most of the quests were intended to show in the Noticeboard quest book specifically. The Noticeboard quest book is special in that it's possible to never be able to acquire some quests in it. Because of that we didn't want to make it a matter of you needed every single one to have the book complete. People would inevitably miss one and it would be pretty frustrating. That being said, I can see how it would be confusing that it shows as complete when you clearly still have things you need to do.
What I've done as a sort of compromise is: if you have unfinished quests in the book it will show as incomplete. The green bar will show you still have things to do. If you've completed everything you currently have, then it will show as complete and display the yellow bar. That is, until you take another noticeboard quest, and the bar will drop back to partially filled and green to show that you now have something to do.
You'll see this change appear in the next update, let us know how it feels.