I bought 1 0f the cargo at Durham Station, then bought 11 more, since I could carry 12 in my Big Dragon. When I sold all 12 at Yukawa Shipyard, the server unregistered me from the event for selling more cargo than I bought, so I didn't get the bonus whatever that was supposed to be! Apparently, the server isn't smart enough to figure out that 1 + 11 = 12 and it forgot that I bought 1 before buying 11 more.
Being robbed of event rewards due to a server glitch is beyond annoying and frustrating!