If a villager tells me he's lost an item, does it mean I can go find it (like the mysterious items you find on the ground sometimes, and then you have to ask around who they belong to)? Or is it just random dialogue?
Is it the text from a lazy villager? He'll talk about how an item of his went missing, and then he'll wonder if everybody else lost their said item. That's random dialogue. Other than that, I've never heard anybody mention a lost item that I remember.