CB Modding help

[slothinator]

Hi all,
I've been trying to mod the holy war CB so that the targeted duchy becomes an independent tributary instead of being absorbed into your realm.
To do this I took a lot of inspiration from the kingdom liberation cb and I didn't expect much trouble.
Strangely enough, when I have yesmen enabled, my CB works as intended but, when I don't, it just ends the war without any territorial changes. I've been wracking my brain for a week now and I can't think of anything else to try. If someone has some advice I would love to hear it.

In the spoiler is my code for the on_success_title section, otherwise, the other sections of the CB are identical to the holy war CB.

Thanks for your help!

Spoiler

on_success_title = {
        create_character = {
            religion = ROOT
            culture = ROOT
            dynasty = random
            random_traits = yes
            female = no
            age = 20
            health = 7
            fertility = 0.7
            attributes = {
                martial = 10
                diplomacy = 10
                stewardship = 10
            }
            flag = is_religious_liberation_ruler
        }
        new_character = {
            remove_trait = cynical
            add_trait = zealous
            wealth = 250
            prestige = 250
            piety = 250
            save_event_target_as = new_ruler
            set_defacto_liege = THIS
        }
        if = {
            limit = {
                has_holder = no
            }
            usurp_title = { target = event_target:new_ruler type = invasion }
        }
        else = {
            event_target:new_ruler = {
                create_title = {
                    tier = DUKE
                    landless = no
                    temporary = no
                    custom_created = yes
                    culture = event_target:new_ruler
                    holder = event_target:new_ruler
                    name = "LIBERATED_KINGDOM"
                    base_title = PREV
                }
            }
        }

        FROM = {
            random_realm_title = {
                limit = {
                    tier = COUNT
                    duchy = { title = PREVPREVPREV }
                }
                location = {
                    event_target:new_ruler = {
                        usurp_title = { target = PREVPREV type = invasion }
                    }
                }
            }
        }

        event_target:new_ruler = {
                vassalize_or_take_under_title = {
                    title = PREV
                    enemy = FROM
                    same_religion = yes # Only vassalize rulers of my religion
                    is_religious = yes
                    type = holy_war
                }
            }
        ROOT = { make_tributary = { who = event_target:new_ruler tributary_type = default }}
    }