I just logged in under "newbie" in s18 and did an /updatestation when I suddenly noticed that there was (active) in front of "cargo mission". I checked and saw that the mission was not activate (there wasn't any mission active at all). Then I logged off and on again: it still did that. However when I changed to "neutral newbie" in s6 (which was not docked) flew to the station and docked, and did /updatestation again; there wasn't any problem at all. I switched back to "newbie" and the problem dissapeared.

this happened to me too.

You need to abort it. This has happened to me several times. Yeah it sucks that the faction will hate you for it, but hey you can make up for it by taking the mission again.

No, the thing is; there is no "abort" button; when I click on the info of that mission it says: "accept" "decline" so there is no "abort".

Sheean...does messaging the mission bot give you the option to abort?

I've seen this too, I do not think the mission is actually active, because you can still accept/decline them (at least for me, and I only noticed this in station which offered 2cargo missions). I think it has something to do with the way they prevent /updatestation from changing the available missions.

You can always abort stuck missions with "/mission abort".