I've noticed that you can ban & eject the founding nation of a region, but that nation can still enter regional controls. Is this a bug or is it meant to work that way?
A UN delegate can ban and eject a regional founder, but regional founders are GOD in their region. They can access the regional controls from outside the region, unban themselves, and kick invaders into the deep blue sea with very little trouble.
Yes, it's meant to work precisely that way. :D Why not repay treachery with treachery?
Founders are the nearest thing to Gods of their region. They have full access to regional controls from inside or outside the region, and they retain those rights even after being restored from the dead.
It's not a bug.