I play Pixelmon on a group server with friends. We just updated to Minecraft Version 1.12.2 and it seems that I can make it in the game fine using the GD Launcher, but once I'm on if I go to mount any pokemon the game will just crash and bring me back to the launcher. I've provided the crash report and hopefully any other information needed.

This is the short crash report and I can send the full one if needed


// There are four lights!

Time: 9/8/21 5:31 PM
Description: Unexpected error

java.lang.NullPointerException: Unexpected error
at com.pixelmonmod.pixelmon.api.pokemon.Pokemon.writeToNBT(Pokemon.java:1830)
at com.pixelmonmod.pixelmon.entities.pixelmon.Entity1Base.func_70014_b(Entity1Base.java:498)
at com.pixelmonmod.pixelmon.entities.pixelmon.Entity2Client.func_70014_b(Entity2Client.java:681)
at com.pixelmonmod.pixelmon.entities.pixelmon.Entity4Interactions.func_70014_b(Entity4Interactions.java:376)
at com.pixelmonmod.pixelmon.entities.pixelmon.Entity6Moves.func_70014_b(Entity6Moves.java:636)
at com.pixelmonmod.pixelmon.entities.pixelmon.EntityPixelmon.func_70014_b(EntityPixelmon.java:587)
at astrotibs.villagenames.handler.EntityInteractHandler.onEntityInteract(EntityInteractHandler.java:214)
at net.minecraftforge.fml.common.eventhandler.ASMEventHandler_2991_EntityInteractHandler_onEntityInteract_EntityInteract.invoke(.dynamic)
at net.minecraftforge.fml.common.eventhandler.ASMEventHandler.invoke(ASMEventHandler.java:90)
at net.minecraftforge.fml.common.eventhandler.EventBus.forgeBridge$post(EventBus.java:756)
at net.minecraftforge.fml.common.eventhandler.EventBus.post(EventBus.java:706)
at net.minecraftforge.common.ForgeHooks.onInteractEntity(ForgeHooks.java:1116)
at net.minecraft.entity.player.EntityPlayer.func_190775_a(EntityPlayer.java:1194)
at net.minecraft.client.multiplayer.PlayerControllerMP.func_187097_a(PlayerControllerMP.java:549)
at net.minecraft.client.Minecraft.func_147121_ag(Minecraft.java:1567)
at net.minecraft.client.Minecraft.func_184117_aA(Minecraft.java:2254)
at net.minecraft.client.Minecraft.func_184118_az(Minecraft.java:2020)
at net.minecraft.client.Minecraft.func_71407_l(Minecraft.java:1808)
at net.minecraft.client.Minecraft.func_71411_J(Minecraft.java:1098)
at net.minecraft.client.Minecraft.func_99999_d(Minecraft.java:398)
at net.minecraft.client.main.Main.main(SourceFile:123)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at net.minecraft.launchwrapper.Launch.launch(Launch.java:135)
at net.minecraft.launchwrapper.Launch.main(Launch.java:28)

We worked it out, it was an interaction with another mod for the mounts!