Error in console: Could not pass event GameEndEvent

[krystian987]

Describe the bug
Error in console:
[15:37:49] [Server thread/ERROR]: Could not pass event GameEndEvent to BedWars1058 v23.12.2
org.bukkit.event.EventException: null
at org.bukkit.plugin.EventExecutor$2.execute(EventExecutor.java:72) ~[patched_1.12.2.jar:git-Paper-1620]
at co.aikar.timings.TimedEventExecutor.execute(TimedEventExecutor.java:78) ~[patched_1.12.2.jar:git-Paper-1620]
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[patched_1.12.2.jar:git-Paper-1620]
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:513) ~[patched_1.12.2.jar:git-Paper-1620]
at com.andrei1058.bedwars.arena.Arena.checkWinner(Arena.java:1985) ~[?:?]
at org.bukkit.craftbukkit.v1_12_R1.scheduler.CraftTask.run(CraftTask.java:64) ~[patched_1.12.2.jar:git-Paper-1620]
at org.bukkit.craftbukkit.v1_12_R1.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:423) ~[patched_1.12.2.jar:git-Paper-1620]
at net.minecraft.server.v1_12_R1.MinecraftServer.D(MinecraftServer.java:840) ~[patched_1.12.2.jar:git-Paper-1620]
at net.minecraft.server.v1_12_R1.DedicatedServer.D(DedicatedServer.java:423) ~[patched_1.12.2.jar:git-Paper-1620]
at net.minecraft.server.v1_12_R1.MinecraftServer.C(MinecraftServer.java:774) ~[patched_1.12.2.jar:git-Paper-1620]
at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:666) ~[patched_1.12.2.jar:git-Paper-1620]
at java.lang.Thread.run(Thread.java:829) [?:?]
Caused by: java.util.ConcurrentModificationException
at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:1043) ~[?:?]
at java.util.ArrayList$Itr.next(ArrayList.java:997) ~[?:?]
at com.andrei1058.bedwars.arena.upgrades.HealPoolTask.removeForArena(HealPoolTask.java:90) ~[?:?]
at com.andrei1058.bedwars.arena.upgrades.HealPoolListner.onEnd(HealPoolListner.java:34) ~[?:?]
at com.destroystokyo.paper.event.executor.asm.generated.GeneratedEventExecutor304.execute(Unknown Source) ~[?:?]
at org.bukkit.plugin.EventExecutor$2.execute(EventExecutor.java:70) ~[patched_1.12.2.jar:git-Paper-1620]
... 11 more

To Reproduce
Steps to reproduce the behavior:
I don't know how to reproduce this error, but it appears very often in the console

System:

• OS: Linux
• Server software Paper
• Server Version 1.12.2
• Plugin Version 23.12.2

[Lsy-291]

Similar to #984