(Story Bug) Pocket Mirror disappeared out of my Inventory

[Darker Bard]

I was trying to give Molly the Pocket Mirror she asked for but the game just suddenly glitched out and skipped the little cut-scene where Arthur hands the requested item over. Now the Pocket Mirror is out of my inventory but the Task to get it is still there. Has anyone experienced this before and is there a workaround to still get the task done?