WRXKiller-GM の投稿を引用：

I just did my First collaboration mission to one of the countries I’m planning on to annex because I got mods where if a country has for collaboration they become a core of your country because it’s like if they are completely working with your people and are exactly like your people now. But to do that that would at least take three collaboration missions which is honestly the only thing spies should be doing when you’re playing single player but for some reason the option is not showing back up in the Mission list so did the developers make it so you can only do it once and once only?