What do you do when all of a sudden your main quest disappears?

Me and my friend were playing tonight and we just finished the quest "To Guard a Guardian" (that quest were you Kill the Black hooded guy that summons that huge monster. Then the Seedseer makes you her emissary.)

So I go off to talk to Miounne and my friend says there quests vanished.

I have noticed other people havehad this happen at this quest, is it an unfix-able glitch?


Please don't suggest looking at the Journal or Map for the quest, its not there, gone. ;-;

It is bugged/glitched and I am scared my friend will not be able to progress.