Job Bug:
If you have 3 Job-Mission that are to be delivered to the same planet the 3rd guy/gal will be outside the loading zone and not execpt its luggage. You have to fullfil one of the 2 others' requests and go to your ship and come back for the 3rd guy to now be in the loading zone and except his package.
My guess it has to do with the fact, that you are only allowed to drop stuff in the loading zone and elevator. This code most likely also prevents the drop of to the 3rd guy.