wait what, is this a custom named vassal or something because i've never seen this occur in game
client state. basically you custom create a vassal and you can add land to it for free. vassal feeding 4EVER!
update:

Rus-Lithuania is now Litvania since Lithuania no longer exists. I keep going to war with the ottomans and taking it's current capital + giving as much as i can to byzantium and Litvania. after that league war (protestant won btw.. held up by me.) the holy roman empire has been at 0% imperial authority. quite fun.