diff --git a/course/lib.php b/course/lib.php
index 5f5535b1218..75498897346 100644
--- a/course/lib.php
+++ b/course/lib.php
@@ -2765,7 +2765,7 @@ function course_add_cm_to_section($courseorid, $modid, $sectionnum, $beforemod =
     course_create_sections_if_missing($courseorid, $sectionnum);
     $section = get_fast_modinfo($courseorid)->get_section_info($sectionnum);
     $modarray = explode(",", trim($section->sequence));
-    if (empty($modarray)) {
+    if (empty($section->sequence)) {
         $newsequence = "$modid";
     } else if ($beforemod && ($key = array_keys($modarray, $beforemod))) {
         $insertarray = array($modid, $beforemod);