diff --git a/src/main/scala/com/fasterxml/jackson/module/scala/ser/MapSerializerModule.scala b/src/main/scala/com/fasterxml/jackson/module/scala/ser/MapSerializerModule.scala
index 773076ea..a81cd363 100644
--- a/src/main/scala/com/fasterxml/jackson/module/scala/ser/MapSerializerModule.scala
+++ b/src/main/scala/com/fasterxml/jackson/module/scala/ser/MapSerializerModule.scala
@@ -8,20 +8,33 @@ import com.fasterxml.jackson.databind.ser.std.StdDelegatingSerializer
 import com.fasterxml.jackson.databind.util.StdConverter
 import com.fasterxml.jackson.module.scala.modifiers.MapTypeModifierModule
 
+import java.util
 import scala.collection.JavaConverters._
 import scala.collection.Map
 
 private class MapConverter(inputType: JavaType, config: SerializationConfig)
   extends StdConverter[Map[_,_],java.util.Map[_,_]]
 {
+  // Making this an inner class avoids deserializaion errors when polymorphic typing
+  // is enabled. In Scala 2.12 `delegate.asJava` happened to be an inner class but
+  // this implementation detail changed in 2.13.
+  //
+  // Tested in DefaultTypingMapDeserializerTest
+  private class MapWrapper[A, B](delegate: Map[A, B]) extends util.AbstractMap[A, B] {
+    private val wrapped = delegate.asJava
+
+    override def entrySet(): util.Set[util.Map.Entry[A, B]] = wrapped.entrySet()
+  }
+
   def convert(value: Map[_,_]): java.util.Map[_,_] = {
     val m = if (config.isEnabled(SerializationFeature.WRITE_NULL_MAP_VALUES)) {
       value
     } else {
       value.filter(_._2 != None)
     }
-    m.asJava
-  }
+    new MapWrapper(m)
+//    m.asJava
+  }``
 
 
   override def getInputType(factory: TypeFactory) = inputType
diff --git a/src/test/scala/com/fasterxml/jackson/module/scala/deser/DefaultTypingMapDeserializerTest.scala b/src/test/scala/com/fasterxml/jackson/module/scala/deser/DefaultTypingMapDeserializerTest.scala
new file mode 100644
index 00000000..057ffe35
--- /dev/null
+++ b/src/test/scala/com/fasterxml/jackson/module/scala/deser/DefaultTypingMapDeserializerTest.scala
@@ -0,0 +1,35 @@
+package com.fasterxml.jackson.module.scala.deser
+
+import com.fasterxml.jackson.databind.ObjectMapper
+import com.fasterxml.jackson.module.scala.DefaultScalaModule
+
+import scala.collection.immutable
+
+class DefaultTypingMapDeserializerTest extends DeserializerTest {
+
+  def module: DefaultScalaModule.type = DefaultScalaModule
+
+  override def newMapper: ObjectMapper = {
+    val mapper = super.newMapper
+    mapper.activateDefaultTyping(mapper.getPolymorphicTypeValidator)
+  }
+
+  "Scala Module" should "deserialize immutable Map when default typing enabled" in {
+    val map = HasMap(immutable.Map("one" -> "one", "two" -> "two"))
+
+    val mapper = newMapper
+
+    val json = mapper.writeValueAsString(map)
+    // Was failing in Scala 2.13+ with:
+    // > Could not resolve type id 'scala.collection.convert.JavaCollectionWrappers$MapWrapper' as a subtype of
+    // > `scala.collection.immutable.Map<java.lang.String,java.lang.String>`: Not a subtype
+    //
+    // prior the changing MapSerializerModule.scala to use an inner class for MapWrapper
+    val read = mapper.readValue(json, classOf[HasMap])
+
+    read shouldEqual map
+  }
+
+}
+
+case class HasMap(m: Map[String, String])