So I took a few of these missions after this great new patch <dripping with sarcasm> Had nothing but issues once I find the item (the mission not being completed). However I have found a way to finish the missions and get the reward. Well it worked for me 3 times last night anyway.

Find the item mission does not complete - zone outside the mission drop the item on the ground wait a few seconds pick it up. That worked once.

The other 2 I zone out of the mission go into the next mission drop the item and pick it back up - the previous mission completes.

See if this works and post your experiences here plz!!