Game crash (Batching chunks: ConcurrentModificationException)

Description: Batching chunks

java.util.ConcurrentModificationException
	at java.util.HashMap$HashIterator.nextNode(HashMap.java:1429)
	at java.util.HashMap$KeyIterator.next(HashMap.java:1453)
	at java.util.AbstractCollection.addAll(AbstractCollection.java:343)
	at java.util.HashSet.<init>(HashSet.java:119)
	at com.google.common.collect.Sets.newHashSet(Sets.java:273)
	at een$c.a(SourceFile:388)
	at een$c.a(SourceFile:225)
	at een$c$b.a(SourceFile:435)
	at een.a(SourceFile:136)
	at een$$Lambda$3494/413560550.apply(Unknown Source)
	at java.util.concurrent.CompletableFuture.uniCompose(CompletableFuture.java:952)
	at java.util.concurrent.CompletableFuture$UniCompose.tryFire(CompletableFuture.java:926)
	at java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:474)
	at java.util.concurrent.CompletableFuture$AsyncRun.run(CompletableFuture.java:1624)
	at java.util.concurrent.CompletableFuture$AsyncRun.exec(CompletableFuture.java:1610)
	at java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:289)
	at java.util.concurrent.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1056)
	at java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1689)
	at java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:157)