diff --git a/bson-kotlinx/src/test/kotlin/org/bson/codecs/kotlinx/KotlinSerializerCodecTest.kt b/bson-kotlinx/src/test/kotlin/org/bson/codecs/kotlinx/KotlinSerializerCodecTest.kt
index 30fc6f7fbb4..ed9e1bfb43a 100644
--- a/bson-kotlinx/src/test/kotlin/org/bson/codecs/kotlinx/KotlinSerializerCodecTest.kt
+++ b/bson-kotlinx/src/test/kotlin/org/bson/codecs/kotlinx/KotlinSerializerCodecTest.kt
@@ -373,7 +373,7 @@ class KotlinSerializerCodecTest {
             |"nestedParameterized": {
             |  "parameterizedDataClass":
             |  {"number": 4.2, "string": "myString", "parameterizedList": [{"name": "embedded1"}]},
-            |  "other": "myOtherString"
+            |  "other": "myOtherString", "optionalOther": "myOptionalOtherString"
             | }
             |}"""
                 .trimMargin()
@@ -381,7 +381,9 @@ class KotlinSerializerCodecTest {
             DataClassWithNestedParameterizedDataClass(
                 "myId",
                 DataClassWithNestedParameterized(
-                    DataClassParameterized(4.2, "myString", listOf(DataClassEmbedded("embedded1"))), "myOtherString"))
+                    DataClassParameterized(4.2, "myString", listOf(DataClassEmbedded("embedded1"))),
+                    "myOtherString",
+                    "myOptionalOtherString"))
 
         assertRoundTrips(expected, dataClass)
     }
diff --git a/bson-kotlinx/src/test/kotlin/org/bson/codecs/kotlinx/samples/DataClasses.kt b/bson-kotlinx/src/test/kotlin/org/bson/codecs/kotlinx/samples/DataClasses.kt
index a58ae541d03..2511c7b0418 100644
--- a/bson-kotlinx/src/test/kotlin/org/bson/codecs/kotlinx/samples/DataClasses.kt
+++ b/bson-kotlinx/src/test/kotlin/org/bson/codecs/kotlinx/samples/DataClasses.kt
@@ -120,7 +120,8 @@ data class DataClassWithNestedParameterizedDataClass(
 @Serializable
 data class DataClassWithNestedParameterized<A, B, C : Number>(
     val parameterizedDataClass: DataClassParameterized<C, A>,
-    val other: B
+    val other: B,
+    val optionalOther: B?
 )
 
 @Serializable data class DataClassWithPair(val pair: Pair<String, Int>)