Kingdom and duchy vassalization

[unmerged(25756)]

I have noticed something weird and I don't know if it is a bug or WAD.

1...I grab a kingdom title and declare war to that king. He also has at least one duke tiltle and count title and some duchies and counties as vassals. I win and get the king's title. After that the defeated king holds his duke and count titles and he becomes my vassal as all his previous vassals.

2...Now the same situation, except that I declare war to a simple duke with counts as vassals. After I have defeated him and got his duke title his previous vassals become mine BUT he becomes independent as a count.

These have happened to me in each case I have encountered so far.
So why in the 2nd situation the defeated duke does not become my vassal as a count?

 

[unmerged(21937)]

Was the duke vassal of some other king?

 

[lenny]

I have noticed something weird and I don't know if it is a bug or WAD.

1...I grab a kingdom title and declare war to that king. He also has at least one duke tiltle and count title and some duchies and counties as vassals. I win and get the king's title. After that the defeated king holds his duke and count titles and he becomes my vassal as all his previous vassals.

2...Now the same situation, except that I declare war to a simple duke with counts as vassals. After I have defeated him and got his duke title his previous vassals become mine BUT he becomes independent as a count.

These have happened to me in each case I have encountered so far.
So why in the 2nd situation the defeated duke does not become my vassal as a count?

I think the problem is due to the fact that demesne provinces of a King or Duke do not have a liege in the save game file, while a Duke title, even if it is held by the King himself, has the King-tag as liege.
So, if you take the King title and leave him his Duke title he will become your vassal. If you also take the Duke title, he will become an independent count.

 

[unmerged(25756)]

I think the problem is due to the fact that demesne provinces of a King or Duke do not have a liege in the save game file, while a Duke title, even if it is held by the King himself, has the King-tag as liege.
So, if you take the King title and leave him his Duke title he will become your vassal. If you also take the Duke title, he will become an independent count.

So, it is a save file format issue and how these titles are connected with each other. Am I correct?
Still, I think it is odd those two situations to have a different outcome. You should either vassalize the defeated or not, regardless of his former title. Is it WAD?