What happened?

Whenever the game renders in a dragon it instantly crashes. All other mobs/structures are generating correctly, only the dragons are causing the crash. I can't spawn them in with spawn eggs or the summon command, and hatching an egg crashes the game.
The crash reports includes the line "Cannot load from object array because "this.growth_stages" is null".
I've tried this with with other mods and with only ice and fire and it still crashes. Also tried different versions and citadel versions but nothing changes. No idea what's causing it.

Minecraft Version

1.20.1

Ice and Fire version

iceandfire-2.1.13-1.20.1-beta-4

Citadel version

citadel-2.5.4-1.20.1

Relevant log output

java.lang.NullPointerException: Cannot load from object array because "this.growth_stages" is null
	at com.github.alexthe666.iceandfire.entity.EntityDragonBase.getRenderSize(EntityDragonBase.java:1811) ~[iceandfire-2.1.13-1.20.1-beta-4%20(1).jar%23172!/:2.1.13-1.20.1-beta-4] {re:classloading}
	at com.github.alexthe666.iceandfire.entity.EntityDragonBase.m_6134_(EntityDragonBase.java:1802) ~[iceandfire-2.1.13-1.20.1-beta-4%20(1).jar%23172!/:2.1.13-1.20.1-beta-4] {re:classloading}

Other Information

• I am using other mods besides Ice and Fire
• I have attached a log file from the session that I have experienced this issue