[2.6.1.1] ''Become King'' ambition not working correctly

[TentacleMayor]

In two starts as the High Chief of Fortriu, I selected the ambition and then started a faction and demanded the title. After enforcing demands, I did not get a notification that the ambition was fulfilled, nor did I get the prestige. The ambition seems to have just been canceled. Major DLCs I *don't* have: Conclave, Reaper's Due, The Old Gods, Horse Lords, The Republic. No mods.

 

[reking]

Is this the right place to post weird CB things I don't understand?
This is me, Jarl Thorbjörn of the Jarldom of Ostlandet. I just recently usurped the Jarldom (nobody owned it when I usurped it).

As you can see the tooltip tells me I can press a claim on the county Vestfold.

However. I have no CB to declare war on this guy! He's just a lowly Chief with that one county.

Couple of other things to note is..
1) my ambition is to become King of Norway, so I should be able to use Subjugate as CB anyway, shouldn't I?
2) The guy is my tributary. If this is the reason I can't attack him, how do I "undo" the tributary? The rest of Norway is my tributary and I want to subjugate them.

No mods.

 

[GinjaNinja32]

@reking 2.6.1 includes a "Release Tributary" button from the character menu (in your picture, immediately above "Declare War"), which will cost 200 prestige if I recall correctly; yes, you should be able to use both Subjugate and De Jure Claim CBs on him once he's not your tributary.