Quest Completed... just not completed. (what happened?)

Hi, let me try to explain.

I joined a room and the host selected the quest "So Notable: Great Maccao" (Hunt 2 Great Maccaos). Few minutes after the quest started the host disconnected, but the rest continued the mission and finished.

After the mission ended I looked at my quest list and "So Notable: Great Maccao" appeared as new (I didn't had it before) but didn't had the check marking it as completed.

why did this happened? it's a glitch? It's a special mission I have to host to completed it? you can't complete a mission if you don't had it in your quest list before?

Thanks for the help.