How does inheritance change on/just prior to death?

[<Redacted>]

tl;dr version: Playing as the primary heir of a king with two kingdom titles and I have one brother, so each of us get one. I'm destined for East Francia, my brother for Bavaria. On the death of my father, brother gets East Francia and I get Bavaria. Checked the most recent autosave and I'm still the heir to EF. What could change in a very short time?

More details:
I picked one of the suggested starts in 867 as Prince Karlmann of East Francia. Comes with two Duchy titles and loads of counties. My brother Ludwig is second heir. My other brother Karl gets Possessed, becomes a Lunatic and a Eunuch (not sure if he starts that way, tbh), and dies of a seizure. So inheritance should be straightforward: I should get EF and Ludwig should get Bavaria, which is what the Line of Succession shows the entire time before my father's death.

In the course of managing everything, I inherit the duchy of Swabia, which is de jure in EF, so I just give it and its counties to my son and heir to alleviate the too many counties penalty somewhat, and because I'll be his king pretty soon (dad is 60+ and not doing great).

When the father dies I'm King! But of Bavaria? Now my son and heir is my brother's vassal. Is this a bug? Could something have happened in a month or two that changes the inheritance without me knowing about it?

Side question: If I were to die right now, would my son and heir get my kingdom title and keep Swabia, so that would just go under Kingdom of Bavaria?

[Emperor2000]

Originally posted by Wade is Right:

tl;dr version: Playing as the primary heir of a king with two kingdom titles and I have one brother, so each of us get one. I'm destined for East Francia, my brother for Bavaria. On the death of my father, brother gets East Francia and I get Bavaria. Checked the most recent autosave and I'm still the heir to EF. What could change in a very short time?

More details:
I picked one of the suggested starts in 867 as Prince Karlmann of East Francia. Comes with two Duchy titles and loads of counties. My brother Ludwig is second heir. My other brother Karl gets Possessed, becomes a Lunatic and a Eunuch (not sure if he starts that way, tbh), and dies of a seizure. So inheritance should be straightforward: I should get EF and Ludwig should get Bavaria, which is what the Line of Succession shows the entire time before my father's death.

In the course of managing everything, I inherit the duchy of Swabia, which is de jure in EF, so I just give it and its counties to my son and heir to alleviate the too many counties penalty somewhat, and because I'll be his king pretty soon (dad is 60+ and not doing great).

When the father dies I'm King! But of Bavaria? Now my son and heir is my brother's vassal. Is this a bug? Could something have happened in a month or two that changes the inheritance without me knowing about it?

Side question: If I were to die right now, would my son and heir get my kingdom title and keep Swabia, so that would just go under Kingdom of Bavaria?

This probably a bug, because Swabia belongs de-jure to East Francia(Germany) in this game and the de-jure Vassals should stay in their de-jure Kingdoms.

But CK3 has a lot of Bugs and I mean A LOT OF BUGS, you only have to look at the Royal Court Event files, the most events from this DLC are missing the right checks and triggers.

[endymionologist]

Your father had just the two kingdoms? In that case, if he changed his primary title before death the order of succession to the kingdoms would change. You do not get a message notification when your liege changes their primary title.
Your son will break away from Germany when you die, if he inherits a kingdom at that time.

[Emperor2000]

Originally posted by endymionologist:

Your father had just the two kingdoms? In that case, if he changed his primary title before death the order of succession to the kingdoms would change. You do not get a message notification when your liege changes their primary title.
Your son will break away from Germany when you die, if he inherits a kingdom at that time.

You do get a notification, when your liege changes their primary title, but I want to say, you get no notification, when your wife is pregnant, because there is a bug with it.

[<Redacted>]

I guess it's a bug then. I'm 99% certain I saw no notification about the primary kingdom changing, but it could have happened just prior to his death so I'd have missed it in the cacophony of massages.

"you get no notification, when your wife is pregnant, because there is a bug with it". That is a strange bug, indeed. Don't think that was the case, here, though.

Thanks for the quick answers.