INFO net.minecraft.server.v1_12_R1.ReportedException: Exception ticking world
28.09 16:07:12 [Server] INFO at net.minecraft.server.v1_12_R1.MinecraftServer.D(MinecraftServer.java:916) ~[patched_1.12.2.jar:git-Paper-1618]
28.09 16:07:12 [Server] INFO at net.minecraft.server.v1_12_R1.DedicatedServer.D(DedicatedServer.java:423) ~[patched_1.12.2.jar:git-Paper-1618]
28.09 16:07:12 [Server] INFO at net.minecraft.server.v1_12_R1.MinecraftServer.C(MinecraftServer.java:774) ~[patched_1.12.2.jar:git-Paper-1618]
28.09 16:07:12 [Server] INFO at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:666) ~[patched_1.12.2.jar:git-Paper-1618]
28.09 16:07:12 [Server] INFO at java.lang.Thread.run(Thread.java:748) [?:1.8.0_222]
28.09 16:07:12 [Server] INFO Caused by: java.util.ConcurrentModificationException
28.09 16:07:12 [Server] INFO at java.util.HashMap$HashIterator.nextNode(HashMap.java:1445) ~[?:1.8.0_222]
28.09 16:07:12 [Server] INFO at java.util.HashMap$KeyIterator.next(HashMap.java:1469) ~[?:1.8.0_222]
28.09 16:07:12 [Server] INFO at net.minecraft.server.v1_12_R1.EntityTracker.a(EntityTracker.java:260) ~[patched_1.12.2.jar:git-Paper-1618]
28.09 16:07:12 [Server] INFO at net.minecraft.server.v1_12_R1.PlayerChunk.b(PlayerChunk.java:152) ~[patched_1.12.2.jar:git-Paper-1618]
28.09 16:07:12 [Server] INFO at net.minecraft.server.v1_12_R1.PlayerChunkMap.flush(PlayerChunkMap.java:214) ~[patched_1.12.2.jar:git-Paper-1618]
28.09 16:07:12 [Server] INFO at net.minecraft.server.v1_12_R1.WorldServer.doTick(WorldServer.java:332) ~[patched_1.12.2.jar:git-Paper-1618]
28.09 16:07:12 [Server] INFO at net.minecraft.server.v1_12_R1.MinecraftServer.D(MinecraftServer.java:905) ~[patched_1.12.2.jar:git-Paper-1618]
28.09 16:07:12 [Server] INFO ... 4 more
28.09 16:07:12 [Server] ERROR Cause of unexpected exception was
28.09 16:07:12 [Server] INFO java.util.ConcurrentModificationException: null
28.09 16:07:12 [Server] INFO at java.util.HashMap$HashIterator.nextNode(HashMap.java:1445) ~[?:1.8.0_222]
28.09 16:07:12 [Server] INFO at java.util.HashMap$KeyIterator.next(HashMap.java:1469) ~[?:1.8.0_222]
28.09 16:07:12 [Server] INFO at net.minecraft.server.v1_12_R1.EntityTracker.a(EntityTracker.java:260) ~[patched_1.12.2.jar:git-Paper-1618]
28.09 16:07:12 [Server] INFO at net.minecraft.server.v1_12_R1.PlayerChunk.b(PlayerChunk.java:152) ~[patched_1.12.2.jar:git-Paper-1618]
28.09 16:07:12 [Server] INFO at net.minecraft.server.v1_12_R1.PlayerChunkMap.flush(PlayerChunkMap.java:214) ~[patched_1.12.2.jar:git-Paper-1618]
28.09 16:07:12 [Server] INFO at net.minecraft.server.v1_12_R1.WorldServer.doTick(WorldServer.java:332) ~[patched_1.12.2.jar:git-Paper-1618]
28.09 16:07:12 [Server] INFO at net.minecraft.server.v1_12_R1.MinecraftServer.D(MinecraftServer.java:905) ~[patched_1.12.2.jar:git-Paper-1618]
28.09 16:07:12 [Server] INFO at net.minecraft.server.v1_12_R1.DedicatedServer.D(DedicatedServer.java:423) ~[patched_1.12.2.jar:git-Paper-1618]
28.09 16:07:12 [Server] INFO at net.minecraft.server.v1_12_R1.MinecraftServer.C(MinecraftServer.java:774) ~[patched_1.12.2.jar:git-Paper-1618]
28.09 16:07:12 [Server] INFO at net.minecraft.server.v1_12_R1.MinecraftServer.run(MinecraftServer.java:666) ~[patched_1.12.2.jar:git-Paper-1618]
28.09 16:07:12 [Server] INFO at java.lang.Thread.run(Thread.java:748) [?:1.8.0_222]