diff --git a/htdocs/eventorganization/class/conferenceorboothattendee.class.php b/htdocs/eventorganization/class/conferenceorboothattendee.class.php
index dbec03466ae..a7c34d2243b 100644
--- a/htdocs/eventorganization/class/conferenceorboothattendee.class.php
+++ b/htdocs/eventorganization/class/conferenceorboothattendee.class.php
@@ -301,7 +301,7 @@ class ConferenceOrBoothAttendee extends CommonObject
 		$result = $this->createCommon($user, $notrigger);
 		if ($result > 0) {
 			$result = $this->fetch($result);
-			if ($result > 0) {
+			if ($result > 0 && empty($this->ref)) {
 				$this->ref = (string) $this->id;
 				$result = $this->update($user);
 			}