If I leave a world and try to join again, it will lost connection and shutdown the world. I need to completely reopen the game and then join a world.
The version is IndustrialUpgrade-1.21.1-3.3.2.9. Neoforge version 21.1.209.
It will happen even with this only.

latest.log

I think the problem should be here
[Server thread/ERROR] [net.minecraft.Util/]: Error saving [1 minecraft:enchanted_book]. Original cause: java.lang.IllegalStateException: Element Reference{ResourceKey[minecraft:enchantment / minecraft:efficiency]=Enchantment Efficiency} is not valid in current registry set
With components:
{
minecraft:stored_enchantments=>ItemEnchantments{enchantments={Reference{ResourceKey[minecraft:enchantment / minecraft:efficiency]=Enchantment Efficiency}=>1}, showInTooltip=true}
minecraft:enchantment_glint_override=>true
minecraft:repair_cost=>0
minecraft:lore=>ItemLore[lines=[], styledLines=[]]
minecraft:enchantments=>ItemEnchantments{enchantments={}, showInTooltip=true}
minecraft:rarity=>UNCOMMON
minecraft:attribute_modifiers=>ItemAttributeModifiers[modifiers=[], showInTooltip=true]
minecraft:max_stack_size=>1
}
With tag: {}
[239月2025 14:49:20.912] [Server thread/ERROR] [net.neoforged.bus.EventBus/EVENTBUS]: Exception caught during firing event: Element Reference{ResourceKey[minecraft:enchantment / minecraft:efficiency]=Enchantment Efficiency} is not valid in current registry set
Index: 2
Listeners:
0: net.neoforged.bus.EventListenerFactory$playerLogin/0x0000013b32d1d400@156149a3
1: net.neoforged.bus.EventListenerFactory$updateRecipe/0x0000013b32d28000@308ded72
2: net.neoforged.bus.EventListenerFactory$loginPlayer/0x0000013b32d29800@c840cdc
3: net.neoforged.bus.EventListenerFactory$onPlayerTick/0x0000013b32d30000@38fc9696
4: net.neoforged.bus.EventListenerFactory$loginPlayer/0x0000013b32d31800@274ffc7b

[Server thread/ERROR] [net.minecraft.server.network.ServerConfigurationPacketListenerImpl/]: Couldn't place player in world
java.lang.IllegalStateException: Element Reference{ResourceKey[minecraft:enchantment / minecraft:efficiency]=Enchantment Efficiency} is not valid in current registry set

the latest version without this problem is 3.3.2.5

try 3.3.2.10

try 3.3.2.10

nice, it work.