This happened to me with "Aba Daba Honeymoon", the sidequest were you teach the Khans how to make chems..

I've taught him all the chems, and the little checkbox thing in the quest log is filled in signifying that it is complete, and when I taught the last one, it gave me the experience points and told me it was complete, but the quest itself is still list up like it's active on my PipBoy and it's still at the top of my list..

anyone else have this happen? would I have had to reload an older save and recomplete it until it went away? I finished it at least 15 game hours ago, so i'm not reloading it, just curious if anyone else ran across anything similar..