[11:58:59 ERROR]: Could not pass event WorldUnloadEvent to ItemsAdder v4.0.3
java.util.ConcurrentModificationException: null
at java.base/java.util.ArrayList$Itr.checkForComodification(ArrayList.java:1095) ~[?:?]
at java.base/java.util.ArrayList$Itr.next(ArrayList.java:1049) ~[?:?]
at ItemsAdder_4.0.3.jar/itemsadder.m.bd.a(SourceFile:1178) ~[ItemsAdder_4.0.3.jar:?]
at ItemsAdder_4.0.3.jar/itemsadder.m.cf.a(SourceFile:468) ~[ItemsAdder_4.0.3.jar:?]
at com.destroystokyo.paper.event.executor.MethodHandleEventExecutor.execute(MethodHandleEventExecutor.java:44) ~[paper-mojangapi-1.21.1-R0.1-SNAPSHOT.jar:?]
at co.aikar.timings.TimedEventExecutor.execute(TimedEventExecutor.java:84) ~[paper-mojangapi-1.21.1-R0.1-SNAPSHOT.jar:1.21.1-130-4d2672e]
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:70) ~[paper-mojangapi-1.21.1-R0.1-SNAPSHOT.jar:?]
at io.papermc.paper.plugin.manager.PaperEventManager.callEvent(PaperEventManager.java:54) ~[paper-1.21.1.jar:1.21.1-130-4d2672e]
at io.papermc.paper.plugin.manager.PaperPluginManagerImpl.callEvent(PaperPluginManagerImpl.java:131) ~[paper-1.21.1.jar:1.21.1-130-4d2672e]
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:628) ~[paper-mojangapi-1.21.1-R0.1-SNAPSHOT.jar:?]
at org.bukkit.craftbukkit.CraftServer.unloadWorld(CraftServer.java:1470) ~[paper-1.21.1.jar:1.21.1-130-4d2672e]
at org.bukkit.Bukkit.unloadWorld(Bukkit.java:866) ~[paper-mojangapi-1.21.1-R0.1-SNAPSHOT.jar:?]
at MythicDungeons-2.0.0-SNAPSHOT.jar/net.playavalon.mythicdungeons.api.parents.instances.AbstractInstance.lambda$dispose$2(AbstractInstance.java:319) ~[MythicDungeons-2.0.0-SNAPSHOT.jar:?]
at MythicDungeons-2.0.0-SNAPSHOT.jar/net.playavalon.mythicdungeons.utility.tasks.ProcessTimer.run(ProcessTimer.java:12) ~[MythicDungeons-2.0.0-SNAPSHOT.jar:?]
at MythicDungeons-2.0.0-SNAPSHOT.jar/net.playavalon.mythicdungeons.api.parents.instances.AbstractInstance.lambda$dispose$4(AbstractInstance.java:319) ~[MythicDungeons-2.0.0-SNAPSHOT.jar:?]
at org.bukkit.craftbukkit.scheduler.CraftTask.run(CraftTask.java:86) ~[paper-1.21.1.jar:1.21.1-130-4d2672e]
at org.bukkit.craftbukkit.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:475) ~[paper-1.21.1.jar:1.21.1-130-4d2672e]
at net.minecraft.server.MinecraftServer.tickChildren(MinecraftServer.java:1724) ~[paper-1.21.1.jar:1.21.1-130-4d2672e]
at net.minecraft.server.dedicated.DedicatedServer.tickChildren(DedicatedServer.java:473) ~[paper-1.21.1.jar:1.21.1-130-4d2672e]
at net.minecraft.server.MinecraftServer.tickServer(MinecraftServer.java:1596) ~[paper-1.21.1.jar:1.21.1-130-4d2672e]
at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1302) ~[paper-1.21.1.jar:1.21.1-130-4d2672e]
at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:329) ~[paper-1.21.1.jar:1.21.1-130-4d2672e]
at java.base/java.lang.Thread.run(Thread.java:1583) ~[?:?]