diff --git a/htdocs/core/class/commonobject.class.php b/htdocs/core/class/commonobject.class.php
index 502d14be39c..789bfb4e8b2 100644
--- a/htdocs/core/class/commonobject.class.php
+++ b/htdocs/core/class/commonobject.class.php
@@ -8430,7 +8430,7 @@ abstract class CommonObject
 
 		// If we have a field ref with a default value of (PROV)
 		if (!$error) {
-			if (key_exists('ref', $this->fields) && $this->fields['ref']['notnull'] > 0 && !is_null($this->fields['ref']['default']) && $this->fields['ref']['default'] == '(PROV)') {
+			if (key_exists('ref', $this->fields) && $this->fields['ref']['notnull'] > 0 && key_exists('default', $this->fields['ref']) && $this->fields['ref']['default'] == '(PROV)') {
 				$sql = "UPDATE ".MAIN_DB_PREFIX.$this->table_element." SET ref = '(PROV".$this->id.")' WHERE (ref = '(PROV)' OR ref = '') AND rowid = ".((int) $this->id);
 				$resqlupdate = $this->db->query($sql);