In your case, I think you're going to just have to do some main story quests. Yes, it seems to be bugged for people who have already cleared all of the main story but I think it's working as intended for players who haven't.

I'm sure that Lasengle is aware that players are in various places in the story. They also occasionally have limited time rewards to encourage people to make main story progress. If it was intended to be a reward for past story progress, then these missions could have been cleared by already having completed the first three missions in Orleans or something and nearly all players would have had the missions completed already. I think they just forgot to take players who already cleared everything into account when coding mission completion for this one. For everyone else, you have to make some minimal main story progress or forfeit the SQ.