SparkR serialize "NA" throws exception

> a <- as.Date(c("2016-11-11", "NA"))
> b <- as.data.frame(a)
> c <- createDataFrame(b)
> dim(c)

16/10/19 10:31:24 ERROR Executor: Exception in task 0.0 in stage 1.0 (TID 1)
java.lang.NegativeArraySizeException
	at org.apache.spark.api.r.SerDe$.readStringBytes(SerDe.scala:110)
	at org.apache.spark.api.r.SerDe$.readString(SerDe.scala:119)
	at org.apache.spark.api.r.SerDe$.readDate(SerDe.scala:128)
	at org.apache.spark.api.r.SerDe$.readTypedObject(SerDe.scala:77)
	at org.apache.spark.api.r.SerDe$.readObject(SerDe.scala:61)
	at org.apache.spark.sql.api.r.SQLUtils$$anonfun$bytesToRow$1.apply(SQLUtils.scala:161)
	at org.apache.spark.sql.api.r.SQLUtils$$anonfun$bytesToRow$1.apply(SQLUtils.scala:160)
	at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:234)
	at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:234)
	at scala.collection.immutable.Range.foreach(Range.scala:160)
	at scala.collection.TraversableLike$class.map(TraversableLike.scala:234)
	at scala.collection.AbstractTraversable.map(Traversable.scala:104)
	at org.apache.spark.sql.api.r.SQLUtils$.bytesToRow(SQLUtils.scala:160)
	at org.apache.spark.sql.api.r.SQLUtils$$anonfun$5.apply(SQLUtils.scala:138)
	at org.apache.spark.sql.api.r.SQLUtils$$anonfun$5.apply(SQLUtils.scala:138)
	at scala.collection.Iterator$$anon$11.next(Iterator.scala:409)
	at scala.collection.Iterator$$anon$11.next(Iterator.scala:409)
	at scala.collection.Iterator$$anon$11.next(Iterator.scala:409)
	at org.apache.spark.sql.catalyst.expressions.GeneratedClass$GeneratedIterator.agg_doAggregateWithoutKey$(Unknown Source)
	at org.apache.spark.sql.catalyst.expressions.GeneratedClass$GeneratedIterator.processNext(Unknown Source)
	at org.apache.spark.sql.execution.BufferedRowIterator.hasNext(BufferedRowIterator.java:43)
	at org.apache.spark.sql.execution.WholeStageCodegenExec$$anonfun$8$$anon$1.hasNext(WholeStageCodegenExec.scala:372)
	at scala.collection.Iterator$$anon$11.hasNext(Iterator.scala:408)
	at org.apache.spark.shuffle.sort.BypassMergeSortShuffleWriter.write(BypassMergeSortShuffleWriter.java:126)
	at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:96)
	at org.apache.spark.scheduler.ShuffleMapTask.runTask(ShuffleMapTask.scala:53)
	at org.apache.spark.scheduler.Task.run(Task.scala:99)
	at org.apache.spark.executor.Executor$TaskRunner.run(Executor.scala:282)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)