[08:29:02 ERROR]: Could not pass event PlayerQuitEvent to Duels v1.0-SNAPSHOT
java.util.ConcurrentModificationException: null
        at java.util.ArrayList.forEach(ArrayList.java:1513) ~[?:?]
        at online.gamerway.duels.MainListener.left(MainListener.java:123) ~[Duels-1.0-SNAPSHOT.jar:?]
        at com.destroystokyo.paper.event.executor.asm.generated.GeneratedEventExecutor107.execute(Unknown Source) ~[?:?]
        at org.bukkit.plugin.EventExecutor.lambda$create$1(EventExecutor.java:69) ~[patched_1.17.1.jar:git-AirplanePurpur-31]
        at co.aikar.timings.TimedEventExecutor.execute(TimedEventExecutor.java:76) ~[patched_1.17.1.jar:git-AirplanePurpur-31]
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:70) ~[patched_1.17.1.jar:git-AirplanePurpur-31]
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:624) ~[patched_1.17.1.jar:git-AirplanePurpur-31]
        at net.minecraft.server.players.PlayerList.disconnect(PlayerList.java:610) ~[patched_1.17.1.jar:git-AirplanePurpur-31]
        at net.minecraft.server.network.ServerGamePacketListenerImpl.onDisconnect(ServerGamePacketListenerImpl.java:2014) ~[app:?]
        at net.minecraft.server.network.ServerGamePacketListenerImpl.disconnect(ServerGamePacketListenerImpl.java:482) ~[app:?]
        at net.minecraft.server.network.ServerGamePacketListenerImpl.disconnect(ServerGamePacketListenerImpl.java:445) ~[app:?]
        at net.minecraft.server.network.ServerGamePacketListenerImpl.tick(ServerGamePacketListenerImpl.java:324) ~[app:?]
        at net.minecraft.network.Connection.tick(Connection.java:555) ~[app:?]
        at net.minecraft.server.network.ServerConnectionListener.tick(ServerConnectionListener.java:201) ~[app:?]
        at net.minecraft.server.MinecraftServer.tickChildren(MinecraftServer.java:1659) ~[patched_1.17.1.jar:git-AirplanePurpur-31]
        at net.minecraft.server.dedicated.DedicatedServer.tickChildren(DedicatedServer.java:494) ~[patched_1.17.1.jar:git-AirplanePurpur-31]
        at net.minecraft.server.MinecraftServer.tickServer(MinecraftServer.java:1480) ~[patched_1.17.1.jar:git-AirplanePurpur-31]
        at net.minecraft.server.MinecraftServer.runServer(MinecraftServer.java:1270) ~[patched_1.17.1.jar:git-AirplanePurpur-31]
        at net.minecraft.server.MinecraftServer.lambda$spin$0(MinecraftServer.java:319) ~[patched_1.17.1.jar:git-AirplanePurpur-31]
        at java.lang.Thread.run(Thread.java:831) [?:?]