Certain missions that require you to purchase cargo and return it to the station have a mistake within them. Let's say the mission tells you to retrieve 4 Carbonic Ores, but that station sells that item, buy 4, leave station, dock. Mission completed in record time.

yea, that happens occasionally. Sometimes you get a mission to deliver cargo or prototypes to the station you are at.

Good catch Lemming! I'm proud of you mate!