If a player kills all zombies with someone dead, they will not advance to the next round.

[paimonian]

Could not pass event EntityDamageByEntityEvent to COM_Zombies v2.3.177
java.util.ConcurrentModificationException
at java.base/java.util.ArrayList$Itr.checkForComodification(ArrayList.java:1013)
at java.base/java.util.ArrayList$Itr.next(ArrayList.java:967)
at comzombies-Universal-2.3.177.jar//com.theprogrammingturkey.comz.game.Game.nextWave(Game.java:548)
at comzombies-Universal-2.3.177.jar//com.theprogrammingturkey.comz.spawning.SpawnManager.removeEntity(SpawnManager.java:155)
at comzombies-Universal-2.3.177.jar//com.theprogrammingturkey.comz.game.Game.damageMob(Game.java:1297)
at comzombies-Universal-2.3.177.jar//com.theprogrammingturkey.comz.listeners.EntityListener.damage(EntityListener.java:112)
at com.destroystokyo.paper.event.executor.asm.generated.GeneratedEventExecutor2381.execute(Unknown Source)
at org.bukkit.plugin.EventExecutor$2.execute(EventExecutor.java:77)
at co.aikar.timings.TimedEventExecutor.execute(TimedEventExecutor.java:77)
at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:70)
at io.papermc.paper.plugin.manager.PaperEventManager.callEvent(PaperEventManager.java:54)
at io.papermc.paper.plugin.manager.PaperPluginManagerImpl.callEvent(PaperPluginManagerImpl.java:126)
at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:617)
at org.bukkit.craftbukkit.v1_20_R3.event.CraftEventFactory.callEvent(CraftEventFactory.java:266)
at org.bukkit.craftbukkit.v1_20_R3.event.CraftEventFactory.callEntityDamageEvent(CraftEventFactory.java:1212)
at org.bukkit.craftbukkit.v1_20_R3.event.CraftEventFactory.callEntityDamageEvent(CraftEventFactory.java:1197)
at org.bukkit.craftbukkit.v1_20_R3.event.CraftEventFactory.handleEntityDamageEvent(CraftEventFactory.java:1128)
at org.bukkit.craftbukkit.v1_20_R3.event.CraftEventFactory.handleEntityDamageEvent(CraftEventFactory.java:1089)
at org.bukkit.craftbukkit.v1_20_R3.event.CraftEventFactory.handleLivingEntityDam

I get this error and remaining zombie count is stuck at 1.