diff --git a/core/lib/Drupal/Core/Config/StorableConfigBase.php b/core/lib/Drupal/Core/Config/StorableConfigBase.php
index a72ddf6..eb21ed8 100644
--- a/core/lib/Drupal/Core/Config/StorableConfigBase.php
+++ b/core/lib/Drupal/Core/Config/StorableConfigBase.php
@@ -180,19 +180,21 @@ protected function castValue($key, $value) {
     if ($element && $element instanceof Property) {
       return $value;
     }
-    if ((is_scalar($value) || $value === NULL) && ($element && $element instanceof PrimitiveInterface)) {
-      // Special handling for integers and floats since the configuration
-      // system is primarily concerned with saving values from the Form API
-      // we have to special case the meaning of an empty string for numeric
-      // types. In PHP this would be casted to a 0 but for the purposes of
-      // configuration we need to treat this as a NULL.
-      $empty_value =  $value === '' && ($element instanceof IntegerInterface || $element instanceof FloatInterface);
-
-      if ($value === NULL || $empty_value) {
-        $value = NULL;
-      }
-      else {
-        $value = $element->getCastedValue();
+    if ((is_scalar($value) || $value === NULL)) {
+      if ($element && $element instanceof PrimitiveInterface) {
+        // Special handling for integers and floats since the configuration
+        // system is primarily concerned with saving values from the Form API
+        // we have to special case the meaning of an empty string for numeric
+        // types. In PHP this would be casted to a 0 but for the purposes of
+        // configuration we need to treat this as a NULL.
+        $empty_value =  $value === '' && ($element instanceof IntegerInterface || $element instanceof FloatInterface);
+
+        if ($value === NULL || $empty_value) {
+          $value = NULL;
+        }
+        else {
+          $value = $element->getCastedValue();
+        }
       }
     }
     else {