diff --git a/modules/openapi-generator/src/main/resources/scala-akka-client/serializers.mustache b/modules/openapi-generator/src/main/resources/scala-akka-client/serializers.mustache
index ea3d00b54e7b..6fcbaa2c35e6 100644
--- a/modules/openapi-generator/src/main/resources/scala-akka-client/serializers.mustache
+++ b/modules/openapi-generator/src/main/resources/scala-akka-client/serializers.mustache
@@ -28,7 +28,8 @@ object Serializers {
   case object LocalDateSerializer extends CustomSerializer[LocalDate]( _ => ( {
     case JString(s) => LocalDate.parse(s)
   }, {
-    JString(d.format(DateTimeFormatter.ISO_LOCAL_DATE))
+    case d: LocalDate =>
+      JString(d.format(DateTimeFormatter.ISO_LOCAL_DATE))
   }))
 {{/java8}}
 {{#joda}}
diff --git a/samples/client/petstore/scala-akka/src/main/scala/org/openapitools/client/core/Serializers.scala b/samples/client/petstore/scala-akka/src/main/scala/org/openapitools/client/core/Serializers.scala
index bb3ac5290ce4..93d491af589a 100644
--- a/samples/client/petstore/scala-akka/src/main/scala/org/openapitools/client/core/Serializers.scala
+++ b/samples/client/petstore/scala-akka/src/main/scala/org/openapitools/client/core/Serializers.scala
@@ -21,7 +21,8 @@ object Serializers {
   case object LocalDateSerializer extends CustomSerializer[LocalDate]( _ => ( {
     case JString(s) => LocalDate.parse(s)
   }, {
-    JString(d.format(DateTimeFormatter.ISO_LOCAL_DATE))
+    case d: LocalDate =>
+      JString(d.format(DateTimeFormatter.ISO_LOCAL_DATE))
   }))
 
  def all: Seq[Serializer[_]] = Seq[Serializer[_]]() :+ DateTimeSerializer :+ LocalDateSerializer
diff --git a/samples/openapi3/client/petstore/scala-akka/src/main/scala/org/openapitools/client/core/Serializers.scala b/samples/openapi3/client/petstore/scala-akka/src/main/scala/org/openapitools/client/core/Serializers.scala
index bb3ac5290ce4..93d491af589a 100644
--- a/samples/openapi3/client/petstore/scala-akka/src/main/scala/org/openapitools/client/core/Serializers.scala
+++ b/samples/openapi3/client/petstore/scala-akka/src/main/scala/org/openapitools/client/core/Serializers.scala
@@ -21,7 +21,8 @@ object Serializers {
   case object LocalDateSerializer extends CustomSerializer[LocalDate]( _ => ( {
     case JString(s) => LocalDate.parse(s)
   }, {
-    JString(d.format(DateTimeFormatter.ISO_LOCAL_DATE))
+    case d: LocalDate =>
+      JString(d.format(DateTimeFormatter.ISO_LOCAL_DATE))
   }))
 
  def all: Seq[Serializer[_]] = Seq[Serializer[_]]() :+ DateTimeSerializer :+ LocalDateSerializer