Living Empress Dowager heir replaced by her younger sister?

[firelordzuko]

In my current game as Thrace, I happened to be blessed with a good dozen daughters and zero sons. I raised my oldest one well and managed to get a matrilineal marriage to the reigning Emperor of Byzantium for her. Throughout his reign, she remained listed as my heir. However, shortly after his death, her younger sister (my second child) was shown as new heir, with the Empress Dowager listed as third in line. Now, I obviously want to be succeeded by the mother of the reigning Empress and not her aunt ... I have called her back to my court and betrothed her (matrilineally) to a foreign king, but nothing changed. I use agnatic-cognatic primogeniture and so does my liege. Is this a glitch?

 

[Veetor]

Do your second daughter has a son? I believe if you have 2 daughters, and the youngest has a son, she has a preference.

 

[Pjstaab]

The son should be the heir, I think. And I think that only works the other way, if the oldest daughter has a son, he inherits before his aunts. I've had this happen too before. And I had to kill of every other sibling before she was back in line to inherit.

 

[Philostherogue]

I've had some really wierd succession changes with no reason. Second Son suddenly becomes heir while first is alive, second daughter becomes heir before either had kids. Oddly though if I resigned and resumed my game it went back to how it should be.