I am playing as Japans daimyo and those rebels seem to spawn when there is no real crysis in the nation, they can enforce their demands pretty much randomly , sometimes rebel demands bar moves very fast , sometimes it wont move at all, but rebels will instantly enforce demands toform a new nation while taking all provices but your capital.
Happed to me, happenedto another superpower on Japan, one rebel army that is getting his ass kicked with one occupied provice can do all of that, take away all of your provices to form a nation.

I have reloaded multiple times just to figure it how it happens, but there isnt much to figure out.

I saw rebel enforcement bar fill up within 2 seconds and then reset to 0, i saw rebel bar never move but rebels enforce their demands with one occupied teritory and just single rebel army.

ALL of that is horrible, considering they spawn without real reason and can take everything away, but biggest issue is that new nation will have superior tech and pretty much maxed out ideas, means it is a super power.

I have managed to beat my own decentralization rebels new country, which happened somewhat early in the game, it took away 90% of my provices but I had 5~ vassals all around him and another superpower ally, all of us took him out quite easily.

But now decentralization rebels took apart my old ally, took ALL but his capital which is pretty much close to half of china ( oh and he was my vassal by that time, as i conquered him and released as vassal.

Rebels had occupied single provice and were in middle of loosing battle, and bam they enforced their demands taking around 20 provices.


I bid my time, saved up money and got my manpower back and went to war, just to see my army get OBLITERATED by 1/3 size stacks , his 1 troop will beat 4 of my, and i am just one tech behind him, since his super tech gave me huge discounts to technology.

Then I noticed that he have 37 ideas, i got 8, china have 7-11.
He even took half of korean peninsula from china while I wasnt looking .

I am not sure if this art of war issue, japan issue or mod issue , but if anyone else encountered them, please share.

I havent posted this in bugs, because I am unsure if its a bug or some incredibly silly art of war feature as I havent played vanila in very long time.