I was trying my luck with the Gothic Invasion Achievement so I tried to get into the HRE first.
I become a tributary of Great Horde to not run into trouble with Crimea.
I No-CB East Friesland and Vassalize them.
I Peace out Munster who attacked the weakened East Friesland for money.
And I take Oldenburg, who also attacked East Friesland.
Now I'm coring Oldenburg, East Friesland is my vassal and I'm a tributary.
I select my army and give the order to recruit extra infantry, which should be recruited in East Friesland.
This works as long as I only recruit one regiment at a time. If I add more, the recruitment stops and I lose both my money and my manpower.
I tried to recreate it in normal mode and It worked as intended when I wasn't a tributary.
I become a tributary of Great Horde to not run into trouble with Crimea.
I No-CB East Friesland and Vassalize them.
I Peace out Munster who attacked the weakened East Friesland for money.
And I take Oldenburg, who also attacked East Friesland.
Now I'm coring Oldenburg, East Friesland is my vassal and I'm a tributary.
I select my army and give the order to recruit extra infantry, which should be recruited in East Friesland.
This works as long as I only recruit one regiment at a time. If I add more, the recruitment stops and I lose both my money and my manpower.
I tried to recreate it in normal mode and It worked as intended when I wasn't a tributary.