Mleap transform not support null values.

I get this error, when i use mleap bundle model. because one of input value is missing. But the mleap cannot process this problem. Anyone can help？
My mleap version: 0.13.0

`scala.MatchError: null
at ml.combust.mleap.core.feature.VectorAssemblerModel$$anonfun$apply$3.apply(VectorAssemblerModel.scala:37)
at ml.combust.mleap.core.feature.VectorAssemblerModel$$anonfun$apply$3.apply(VectorAssemblerModel.scala:37)
at scala.collection.immutable.Stream.foreach(Stream.scala:594)
at ml.combust.mleap.core.feature.VectorAssemblerModel.apply(VectorAssemblerModel.scala:37)
at ml.combust.mleap.runtime.transformer.feature.VectorAssembler$$anonfun$1.apply(VectorAssembler.scala:18)
at ml.combust.mleap.runtime.transformer.feature.VectorAssembler$$anonfun$1.apply(VectorAssembler.scala:18)
at ml.combust.mleap.runtime.frame.Row$class.udfValue(Row.scala:241)
at ml.combust.mleap.runtime.frame.ArrayRow.udfValue(ArrayRow.scala:17)
at ml.combust.mleap.runtime.frame.Row$class.withValue(Row.scala:221)
at ml.combust.mleap.runtime.frame.ArrayRow.withValue(ArrayRow.scala:17)
at ml.combust.mleap.runtime.frame.DefaultLeapFrame$$anonfun$withColumn$1$$anonfun$apply$2$$anonfun$2.apply(DefaultLeapFrame.scala:54)
at ml.combust.mleap.runtime.frame.DefaultLeapFrame$$anonfun$withColumn$1$$anonfun$apply$2$$anonfun$2.apply(DefaultLeapFrame.scala:54)
at scala.collection.immutable.Stream$$anonfun$map$1.apply(Stream.scala:418)
at scala.collection.immutable.Stream$$anonfun$map$1.apply(Stream.scala:418)
at scala.collection.immutable.Stream$Cons.tail(Stream.scala:1233)
at scala.collection.immutable.Stream$Cons.tail(Stream.scala:1223)
at scala.collection.immutable.Stream$$anonfun$map$1.apply(Stream.scala:418)
at scala.collection.immutable.Stream$$anonfun$map$1.apply(Stream.scala:418)
at scala.collection.immutable.Stream$Cons.tail(Stream.scala:1233)
at scala.collection.immutable.Stream$Cons.tail(Stream.scala:1223)
at scala.collection.immutable.Stream$$anonfun$map$1.apply(Stream.scala:418)
at scala.collection.immutable.Stream$$anonfun$map$1.apply(Stream.scala:418)
at scala.collection.immutable.Stream$Cons.tail(Stream.scala:1233)
at scala.collection.immutable.Stream$Cons.tail(Stream.scala:1223)
at scala.collection.immutable.StreamIterator$$anonfun$next$1.apply(Stream.scala:1120)
at scala.collection.immutable.StreamIterator$$anonfun$next$1.apply(Stream.scala:1120)
at scala.collection.immutable.StreamIterator$LazyCell.v$lzycompute(Stream.scala:1109)
at scala.collection.immutable.StreamIterator$LazyCell.v(Stream.scala:1109)
at scala.collection.immutable.StreamIterator.hasNext(Stream.scala:1114)
at scala.collection.convert.Wrappers$IteratorWrapper.hasNext(Wrappers.scala:30)`