The Imperialism CB uses a wargoal of "Take [Country]". Not only is the tooltip for it vague and doesn't really explain what the wargoal actually is beyond "occupy stuff", but the threshold to trigger ticking warscore seems either bugged or extremely unfair. I have all of Castile occupied and have a lot of their colonies occupied, and yet I cannot get any warscore because Castile for some reason is still getting ticking warscore. I'm in a situation where I have to white peace because, even though Castile would accept whatever I offer him, I can't actually demand anything because I don't have 10 warscore.
I don't know why it doesn't just use the "Control Capital" wargoal like the EU4 version of the CB. That would be much more reasonable and help avoid this situation. If not that, the threshold to trigger ticking should be adjusted to be a bit less ridiculous because the way it is now makes the CB extremely awkward if not detrimental to use on very large countries and/or colonizers.