NPE on Hive Hook Proto Log Writer

023-04-10T17:43:44,226 ERROR [Hive Hook Proto Log Writer 0]: hooks.HiveHookEventProtoPartialBuilder (:()) - Unexpected exception while serializing json.
java.lang.NullPointerException: null
	at org.apache.hadoop.hive.ql.exec.ExplainTask.outputPlan(ExplainTask.java:986) ~[hive-exec-3.1.4.3.2.2.0-1.jar:3.1.4.3.2.2.0-1]
	at org.apache.hadoop.hive.ql.exec.ExplainTask.outputPlan(ExplainTask.java:908) ~[hive-exec-3.1.4.3.2.2.0-1.jar:3.1.4.3.2.2.0-1]
	at org.apache.hadoop.hive.ql.exec.ExplainTask.outputPlan(ExplainTask.java:1263) ~[hive-exec-3.1.4.3.2.2.0-1.jar:3.1.4.3.2.2.0-1]
	at org.apache.hadoop.hive.ql.exec.ExplainTask.outputStagePlans(ExplainTask.java:1408) ~[hive-exec-3.1.4.3.2.2.0-1.jar:3.1.4.3.2.2.0-1]
	at org.apache.hadoop.hive.ql.exec.ExplainTask.getJSONPlan(ExplainTask.java:367) ~[hive-exec-3.1.4.3.2.2.0-1.jar:3.1.4.3.2.2.0-1]
	at org.apache.hadoop.hive.ql.exec.ExplainTask.getJSONPlan(ExplainTask.java:268) ~[hive-exec-3.1.4.3.2.2.0-1.jar:3.1.4.3.2.2.0-1]
	at org.apache.hadoop.hive.ql.hooks.HiveHookEventProtoPartialBuilder.getExplainJSON(HiveHookEventProtoPartialBuilder.java:84) ~[hive-exec-3.1.4.3.2.2.0-1.jar:3.1.4.3.2.2.0-1]
	at org.apache.hadoop.hive.ql.hooks.HiveHookEventProtoPartialBuilder.addQueryObj(HiveHookEventProtoPartialBuilder.java:75) ~[hive-exec-3.1.4.3.2.2.0-1.jar:3.1.4.3.2.2.0-1]
	at org.apache.hadoop.hive.ql.hooks.HiveHookEventProtoPartialBuilder.build(HiveHookEventProtoPartialBuilder.java:55) ~[hive-exec-3.1.4.3.2.2.0-1.jar:3.1.4.3.2.2.0-1]
	at org.apache.hadoop.hive.ql.hooks.HiveProtoLoggingHook$EventLogger.writeEvent(HiveProtoLoggingHook.java:312) ~[hive-exec-3.1.4.3.2.2.0-1.jar:3.1.4.3.2.2.0-1]
	at org.apache.hadoop.hive.ql.hooks.HiveProtoLoggingHook$EventLogger.lambda$handle$1(HiveProtoLoggingHook.java:274) ~[hive-exec-3.1.4.3.2.2.0-1.jar:3.1.4.3.2.2.0-1]
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) ~[?:1.8.0_362]
	at java.util.concurrent.FutureTask.run(FutureTask.java:266) ~[?:1.8.0_362]
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180) ~[?:1.8.0_362]
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293) ~[?:1.8.0_362]
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) ~[?:1.8.0_362]
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) ~[?:1.8.0_362]
	at java.lang.Thread.run(Thread.java:750) [?:1.8.0_362] 

explain.initialize(hookContext.getQueryState(), plan, null, null);