Correct. Sounds to me as though you've met them firsthand. And yes, there is a reason for them. In the past, we used special incantations and enchantments on the materials used to make the lanterns to usher the deceased and malevolent spirits back to the spirit realm.

My associates at the festival noticed it was recurring once again, so we who remained in the temple worked tirelessly to send them to the Beyond where the dead may find peace.