Hi there!
Thank you for the report. The described situation is working as designed, confederate partition is designed to create titles for younger children if these can be created. Holding 1 kingdom title with second one not yet created will create it for the child that stands to inherit.
You can either change your succession law to partition, thus disallowing the younger heirs to create titles to rule or by creating an empire title, where you won't lose land.
Hopefully that clarifies the situation.
Thank you for the report. The described situation is working as designed, confederate partition is designed to create titles for younger children if these can be created. Holding 1 kingdom title with second one not yet created will create it for the child that stands to inherit.
You can either change your succession law to partition, thus disallowing the younger heirs to create titles to rule or by creating an empire title, where you won't lose land.
Hopefully that clarifies the situation.