[16:42:46 WARN]: [Queue] Task #20 for Queue v0.1 generated an exception
java.util.ConcurrentModificationException: null
        at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:901) ~[?:1.8.0_121]
        at java.util.ArrayList$Itr.next(ArrayList.java:851) ~[?:1.8.0_121]
        at com.mr_replete.queue.tasks.QueueTask$1.run(QueueTask.java:30) ~[?:?]
        at org.bukkit.craftbukkit.v1_12_R1.scheduler.CraftTask.run(CraftTask.java:58) ~[patched_1.12.2.jar:git-Paper-1332]
        at org.bukkit.craftbukkit.v1_12_R1.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:356) [patched_1.12.2.jar:git-Paper-1332]
        at net.minecraft.server.v1_12_R1.MinecraftServer.D(MinecraftServer.java:833) [patched_1.12.2.jar:git-Paper-1332]
        at net.minecraft.server.v1_12_R1.DedicatedServer.D(DedicatedServer.java:426) [patched_1.12.2.jar:git-Paper-1332]
        at net.minecraft.server.v1_12_R1.MinecraftServer.C(MinecraftServer.java:767) [patched_1.12.2.jar:git-Paper-1332]
        at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:665) [patched_1.12.2.jar:git-Paper-1332]
        at java.lang.Thread.run(Thread.java:745) [?:1.8.0_121]