For the record, this is still happening. The only issue is this time, I'm not lord of a region that can be made into a Duchy. (Which, if someone has both the power and mercy, I'd ask them to reverse my dissolving of my Duchy...)
This also begs the question: If Duchies can be regionless and are no longer tied to a city, why must a Duchy be initiated in one of those specific types of regions?