Balancer stuck when moving striped blocks due to NPE

21/10/11 06:11:26 WARN balancer.Dispatcher: Dispatcher thread failed
java.lang.NullPointerException
        at org.apache.hadoop.hdfs.server.balancer.Dispatcher$PendingMove.markMovedIfGoodBlock(Dispatcher.java:289)
        at org.apache.hadoop.hdfs.server.balancer.Dispatcher$PendingMove.chooseBlockAndProxy(Dispatcher.java:272)
        at org.apache.hadoop.hdfs.server.balancer.Dispatcher$PendingMove.access$2500(Dispatcher.java:236)
        at org.apache.hadoop.hdfs.server.balancer.Dispatcher$Source.chooseNextMove(Dispatcher.java:899)
        at org.apache.hadoop.hdfs.server.balancer.Dispatcher$Source.dispatchBlocks(Dispatcher.java:958)
        at org.apache.hadoop.hdfs.server.balancer.Dispatcher$Source.access$3300(Dispatcher.java:757)
        at org.apache.hadoop.hdfs.server.balancer.Dispatcher$2.run(Dispatcher.java:1226)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
        at java.lang.Thread.run(Thread.java:748)