diff --git a/third_party/terraform/tests/resource_container_cluster_test.go.erb b/third_party/terraform/tests/resource_container_cluster_test.go.erb
index 7c9bdb16e857..a0a35cfa62ff 100644
--- a/third_party/terraform/tests/resource_container_cluster_test.go.erb
+++ b/third_party/terraform/tests/resource_container_cluster_test.go.erb
@@ -2864,7 +2864,7 @@ resource "google_container_cluster" "with_node_config" {
     }
 
     // Updatable fields
-    image_type = "COS"
+    image_type = "cos"
   }
 }
 `, clusterName)
diff --git a/third_party/terraform/utils/node_config.go.erb b/third_party/terraform/utils/node_config.go.erb
index 20e334057ae2..8e7ff6dd6f16 100644
--- a/third_party/terraform/utils/node_config.go.erb
+++ b/third_party/terraform/utils/node_config.go.erb
@@ -73,6 +73,7 @@ func schemaNodeConfig() *schema.Schema {
 					Type:     schema.TypeString,
 					Optional: true,
 					Computed: true,
+					DiffSuppressFunc: caseDiffSuppress,
 				},
 
 				"labels": {