Bug: Unable to turn in The Missing Mechanical Parts quest. See screen shot. What is suppose to happen: After completing jump quest and collecting 10 mechanical parts, talk to Assistant Cheng to complete quest.
Can be completed but it's not very intuitive. Worked for me by using the talk option with Assistant Cheng at the end of the jump quest map. You never get any 'quest completed' jingle message or 'quest hand in book' above the NPC with this one and even with all 10 parts he has the same quest in progress dialogue if you click the quest option.