Without knowing the mission in question i think you can always abandon a mission and restart it ? just a quick reply probs someone else has a better helping hint...
Edit: i noticed now you talking about "sold to merchant" ..most mission that requires you to craft a item you have to turn in the crafted goods to the mission giver NPC . Could it be just that ?
Edit: i noticed now you talking about "sold to merchant" ..most mission that requires you to craft a item you have to turn in the crafted goods to the mission giver NPC . Could it be just that ?