"Expand Duchy" decision causes territories with no de jure kingdom or empire

[IhateTrains]

For several patches now, there has been a decision "expand duchy" allowing you to add a province to a duchy. Converter sometimes creates duchies without de jure kingdoms, which results in that when this decision is used, a territory is created without a de jure kingdom and empire. Maybe it would be a good idea to assign duchies a de jure kingdom according to their capital?

[IhateTrains]

The decision is documented here:
https://ck3.paradoxwikis.com/Ruler_decisions