For everyone having an issue with the Expand Duchy of Anjou decision, I found a fix that worked for me.

In the file norman_scripted_effects.txt, replace the expand_d_anjou_scripted_effect with this:

expand_d_anjou_scripted_effect = {
scope:founder = {
title:c_tourraine = { set_de_jure_liege_title = title:d_anjou }
}
}


In the norman_decisions.txt file, change expand_anjou_decision with this:

expand_anjou_decision = {
picture = "gfx/interface/illustrations/decisions/decision_destiny_goal.dds"
major = yes

ai_check_interval = 120

desc = expand_anjou_decision_desc

is_shown = {
has_game_rule = norman_flavor_pack_enabled_true
culture = culture:norman
is_landed = yes
highest_held_title_tier >= tier_duchy
has_title = title:d_anjou
NOT = {
is_target_in_global_variable_list = {
name = unavailable_unique_decisions
target = flag:expand_anjou_decision
}
}
NOT = { title:c_tourraine.duchy = title:d_anjou }
}

is_valid = {
completely_controls = title:d_anjoua
completely_controls = title:c_tourraine
NOT = { title:c_tourraine.duchy = title:d_anjou }

}

is_valid_showing_failures_only = {
is_imprisoned = no
is_available_adult = yes
is_at_war = no
}

effect = {
add_to_global_variable_list = {
name = unavailable_unique_decisions
target = flag:expand_anjou_decision
}

save_scope_as = founder
show_as_tooltip = { expand_d_anjou_scripted_effect = yes }
trigger_event = { id = norman_major_decisions.0000 }
}

cost = {
gold = 150
}

ai_potential = {
always = yes
}

ai_will_do = {
base = 100
}
}