Index: moodle/mod/lamslesson/lib.php
===================================================================
diff -u -r273e0709e68cb41df7fe41f1be07add6f25f69c6 -r1943f502b59443a3ebb2f4c95eb470df758e6ed1
--- moodle/mod/lamslesson/lib.php	(.../lib.php)	(revision 273e0709e68cb41df7fe41f1be07add6f25f69c6)
+++ moodle/mod/lamslesson/lib.php	(.../lib.php)	(revision 1943f502b59443a3ebb2f4c95eb470df758e6ed1)
@@ -768,7 +768,7 @@
 
 		$listofcontexts = '('.$sitecontext->id.')'; // must be site
 	}
-	$sql = "SELECT u.id
+	$sql = "SELECT DISTINCT u.id
 		FROM {user} u INNER JOIN {role_assignments} r ON u.id=r.userid
 		WHERE r.contextid IN $listofcontexts OR r.contextid=$context->id
 		AND u.deleted=0 AND u.username!='guest'";