Which trait causes the feels oppressed trait in tributary states?

[Ryofu]

I know that the rebellious trait will give this trait but i am encountering in my current game a tributary state where the ruler does not have the rebellious trait but he has a whopping -150 to my diplomatic relationship with him because of the feels oppressed by the huns trait

i am curious what other traits might be causing this

[Zhayedan]

i think it's random
there are also a bunch of other random traits your puppet sates might get such as "raiding against" and "agents activity against" that puppet states come with when the game starts or you subjugate them

[crowe15]

rebellious

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rebellious