http://www.youtube.com/watch?v=_n8bRfvcoM4

.
This video Show`s Proof of what i mean
(Mission rank 2-2 (time to get crafty)
Doesnt allow me to start the mission.
I confirm for the items to be traded for the Mission rewards , and I click the start button instead of exchanging .
It show`s a lock symbol.

Im new to this game so i dont really know if this is a bug or not