I recently tested them, and the power:malice_stage1_1 function was corrupted, that is now fixed, I believe this is a general issue with schedule functions, I'll send the two files here.
rein:malice
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execute in minecraft:the_nether if entity @a[tag=Malice_Enabled] at @e[tag=Malice_STAGE1] run summon minecraft:skeleton -210 71 -4 {CustomName:"\"Malicious Guardian\"",CustomNameVisible:1,PersistenceRequired:1b,CanPickUpLoot:0b,Health:150,Attributes:[{Name:"generic.max_health",Base:300},{Name:"generic.follow_range",Base:100},{Name:"generic.knockback_resistance",Base:0.5f}],Silent:1,HandItems:[{id:"minecraft:diamond_sword",tag:{display:{Name:'{"text":"Malicious Sword"}'},Unbreakable:1b,Enchantments:[{id:sharpness,lvl:5},{id:fire_aspect,lvl:2}]},Count:1},{}],ArmorItems:[{tag:{display:{Name:'{"text":"Malicious Boots"}'},Unbreakable:1b,Enchantments:[{id:protection,lvl:5},{id:thorns,lvl:10}]},id:"minecraft:diamond_boots",Count:1},{tag:{display:{Name:'{"text":"Malicious Leggings"}'},Unbreakable:1b,Enchantments:[{id:protection,lvl:5},{id:thorns,lvl:10}]},id:"minecraft:diamond_leggings",Count:1},{tag:{display:{Name:'{"text":"Malicious Chestplate"}'},Unbreakable:1b,Enchantments:[{id:protection,lvl:5},{id:thorns,lvl:10}]},id:"minecraft:diamond_chestplate",Count:1},{id:"minecraft:diamond_helmet",Count:1,tag:{display:{Name:'{"text":"Malicious Helmet"}'},Unbreakable:1b,Enchantments:[{id:protection,lvl:5},{id:thorns,lvl:10}]}}],ActiveEffects:[{Id:5,Amplifier:2,Duration:2147483647,ShowParticles:0b},{Id:11,Amplifier:0,Duration:2147483647,ShowParticles:0b},{Id:12,Amplifier:4,Duration:2147483647,ShowParticles:0b},{Id:14,Amplifier:0,Duration:2147483647,ShowParticles:0b}],Tags:["Enemy","Malicious_Guardian"],Team:Enemy}
execute in minecraft:the_nether if entity @a[tag=Malice_Enabled] at @e[tag=Malice_STAGE1] run summon minecraft:blaze -210 71 -4 {CustomName:"\"Reinforcement\"",CustomNameVisible:1a,PersistenceRequired:1b,Health:250,Attributes:[{Name:"generic.max_health",Base:125},{Name:"generic.follow_range",Base:500},{Name:"generic.movement_speed",Base:0.5f}],Silent:1,ActiveEffects:[{Id:5,Amplifier:2,Duration:2147483647,ShowParticles:0b},{Id:12,Amplifier:6,Duration:2147483647,ShowParticles:0b},{Id:14,Amplifier:0,Duration:2147483647,ShowParticles:0b}],Tags:["Enemy"],Team:Enemy}
execute in minecraft:the_nether if entity @a[tag=Malice_Enabled] at @e[tag=Malice_STAGE1] run summon minecraft:blaze -210 71 -4 {CustomName:"\"Reinforcement\"",CustomNameVisible:1a,PersistenceRequired:1b,Health:250,Attributes:[{Name:"generic.max_health",Base:125},{Name:"generic.follow_range",Base:500},{Name:"generic.movement_speed",Base:0.5f}],Silent:1,ActiveEffects:[{Id:5,Amplifier:2,Duration:2147483647,ShowParticles:0b},{Id:12,Amplifier:6,Duration:2147483647,ShowParticles:0b},{Id:14,Amplifier:0,Duration:2147483647,ShowParticles:0b}],Tags:["Enemy"],Team:Enemy}
execute if entity @a[tag=Malice_Enabled] run schedule function rein:malice 450s
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power:malice_stage1_1
-----------------------------------execute if entity @e[tag=Malice_STAGE1] if entity @a[tag=Malice_Enabled] run tellraw @a ["",{"text":"[MALICE]:","bold":true,"color":"dark_red"},{"text":" Fireball Crash!"}]
execute if entity @e[tag=Malice_STAGE1] if entity @a[tag=Malice_Enabled] in minecraft:the_nether at @a run summon minecraft:fireball ~ ~25 ~ {Motion:[0.0,-0.1,0.0],power:[0.0,-0.1,0.0],ExplosionPower:3}
execute if entity @e[tag=Malice_STAGE1] if entity @a[tag=Malice_Enabled] in minecraft:the_nether at @a run summon minecraft:fireball ~ ~27 ~ {Motion:[0.0,-0.1,0.0],power:[0.0,-0.1,0.0],ExplosionPower:5}
execute if entity @e[tag=Malice_STAGE1] if entity @a[tag=Malice_Enabled] in minecraft:the_nether at @a run summon minecraft:fireball ~ ~29 ~ {Motion:[0.0,-0.1,0.0],power:[0.0,-0.1,0.0],ExplosionPower:7}
execute if entity @e[tag=Malice_STAGE1] if entity @a[tag=Malice_Enabled] in minecraft:the_nether at @a run summon minecraft:fireball ~ ~31 ~ {Motion:[0.0,-0.1,0.0],power:[0.0,-0.1,0.0],ExplosionPower:9}
execute if entity @e[tag=Malice_STAGE1] if entity @a[tag=Malice_Enabled] in minecraft:the_nether at @a run summon minecraft:fireball ~ ~33 ~ {Motion:[0.0,-0.1,0.0],power:[0.0,-0.1,0.0],ExplosionPower:15}
execute if entity @e[tag=Malice_STAGE1] if entity @a[tag=Malice_Enabled] run schedule function power:malice_stage1_2_1 45s
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