diff --git a/CRM/Core/BAO/CustomGroup.php b/CRM/Core/BAO/CustomGroup.php
index 0d76d4672fdb..86d5069ee7f4 100644
--- a/CRM/Core/BAO/CustomGroup.php
+++ b/CRM/Core/BAO/CustomGroup.php
@@ -652,13 +652,13 @@ protected static function validateSubTypeByEntity($entityType, $subType) {
       return $subType;
     }
     $contactTypes = civicrm_api3('Contact', 'getoptions', array('field' => 'contact_type'));
-    if ($entityType != 'Contact' && !in_array($entityType, $contactTypes['values'])) {
+    if ($entityType != 'Contact' && !array_key_exists($entityType, $contactTypes['values'])) {
       // Not quite sure if we want to fail this hard. But quiet ignore would be pretty bad too.
       // Am inclined to go with this for RC release & considering softening.
       throw new CRM_Core_Exception('Invalid Entity Filter');
     }
     $subTypes = civicrm_api3('Contact', 'getoptions', array('field' => 'contact_sub_type'));
-    if (!isset($subTypes['values'][$subType])) {
+    if (!array_key_exists($subType, $subTypes['values'])) {
       // Same comments about fail hard as above.
       throw new CRM_Core_Exception('Invalid Filter');
     }