Bug (?) Quest : Recruits do not suffice

Hi I've got a problem with the quest : Recruits do not suffice

Bug-Template

Nick: moebus666
Your timezone (and country): Eastern Standard Time (Canada, but region is United States of America
Date when it happened: 2014 June 16
Hour when it occurred: around 15:00
Your player level: 31
Which browser do you use (i.e. Firefox, Internet Explorer...)?: Firefox
What version is your browser? 29.0.1
What Flashplayer version do you use? shockwave flash 13.0.0.214
Which Extensions/Addons do you use? Extensions: Adblock Plus 2.6.3, Download Helper 4.9.22, FireFTP 2.0.19, Greasemonkey 1.15 | Addons: Shockwave flash 13.0.0.214
Did you try to delete the cache and cookies? no but I tried on two different computers. Nevertheless, I will do it right now (and edit or reply to this post if situation is improved)
Did you relog (log in again)? yes

Please describe all steps you took until the bug happened or how the bug could be reproduced.
Describe only 1 bug per post. Don't mix up issues!
Does this bug only happened once, or does is occur every time you do this action?
If possible: Add a screenshot or the link to it here:

The problem is that the production of the 6 requested commodities is above 0, it's all green in the quest panel but I don't receive the reward.

See the picture here: http://postimg.org/image/5xamwxo3j/
(the 6 box are green)

Thanks for your attention.
Moeb

I've logout, flushed cookies and cache memory, reloged and the quest is still not completed despite it seems all done.

Well... finally, I reactivated my Lettersmith (stopped to complete the quest). It made the production of iron ore decreased below 0. Then I stopped it again and I when the iron ore production rose above zero I finally received the reward...