diff --git a/mmv1/third_party/terraform/services/storage/resource_storage_bucket_object.go b/mmv1/third_party/terraform/services/storage/resource_storage_bucket_object.go
index c0f2b63d8920..1eece93ca437 100644
--- a/mmv1/third_party/terraform/services/storage/resource_storage_bucket_object.go
+++ b/mmv1/third_party/terraform/services/storage/resource_storage_bucket_object.go
@@ -390,6 +390,9 @@ func resourceStorageBucketObjectUpdate(d *schema.ResourceData, meta interface{})
 	if hasRetentionChanges {
 		if v, ok := d.GetOk("retention"); ok {
 			res.Retention = expandObjectRetention(v)
+		} else {
+			res.Retention = nil
+			res.NullFields = append(res.NullFields, "Retention")
 		}
 	}
 
diff --git a/mmv1/third_party/terraform/services/storage/resource_storage_bucket_object_test.go b/mmv1/third_party/terraform/services/storage/resource_storage_bucket_object_test.go
index 37386f9a3840..fbad5d66339b 100644
--- a/mmv1/third_party/terraform/services/storage/resource_storage_bucket_object_test.go
+++ b/mmv1/third_party/terraform/services/storage/resource_storage_bucket_object_test.go
@@ -436,13 +436,13 @@ func TestAccStorageObject_retention(t *testing.T) {
 		CheckDestroy:             testAccStorageObjectDestroyProducer(t),
 		Steps: []resource.TestStep{
 			{
-				Config: testGoogleStorageBucketsObjectRetention(bucketName, "2040-01-01T02:03:04Z"),
+				Config: testGoogleStorageBucketsObjectRetention(bucketName, "2040-01-01T02:03:04.000Z"),
 				Check: resource.ComposeTestCheckFunc(
 					testAccCheckGoogleStorageObject(t, bucketName, objectName, dataMd5),
 				),
 			},
 			{
-				Config: testGoogleStorageBucketsObjectRetention(bucketName, "2040-01-02T02:03:04Z"),
+				Config: testGoogleStorageBucketsObjectRetention(bucketName, "2040-01-02T02:03:04.000Z"),
 				Check: resource.ComposeTestCheckFunc(
 					testAccCheckGoogleStorageObject(t, bucketName, objectName, dataMd5),
 				),