I restored a ghost to life using the Reanimation and Sunlight spells (Witch, Supernatural) and invited her to move in. A member of my household then attempted to woo her, and they became boyfriend-girlfriend and had a full relationship bar. However, the option to Propose Marriage never showed up.
They took a family trip to China, at which point my household member broke up with the former ghost and, upon re-romancing her, finally received the option to Propose Marriage. However, when they returned home, the option disappeared, despite my breaking them up again.
Does anyone know how to fix this error? I'm planning to have them travel again, just to see if they can marry successfully while on vacation.