[18:05:13 WARN]: [MrDungeons] Task #19 for MrDungeons v1.0 generated an exception
java.util.ConcurrentModificationException: null
        at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:911) ~[?:1.8.0_352]
        at java.util.ArrayList$Itr.next(ArrayList.java:861) ~[?:1.8.0_352]
        at me.sturm.mrdungeons.dungeon.Dungeon.respawn(Dungeon.kt:52) ~[?:?]
        at me.sturm.mrdungeons.dungeon.DungeonMaster.respawn(DungeonMaster.kt:30) ~[?:?]
        at me.sturm.mrdungeons.dungeon.DungeonSpawnTimer$runnable$1.run(DungeonSpawnTimer.kt:16) ~[?:?]
        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:750) [?:1.8.0_352]