diff --git a/blocks/glossary_random/block_glossary_random.php b/blocks/glossary_random/block_glossary_random.php
index c0f1a7a5531..db094c95fe5 100644
--- a/blocks/glossary_random/block_glossary_random.php
+++ b/blocks/glossary_random/block_glossary_random.php
@@ -169,7 +169,7 @@ class block_glossary_random extends block_base {
         $modinfo = get_fast_modinfo($this->config->courseid);
         // If deleted glossary or non-global glossary on different course page, then reset.
         if (!isset($modinfo->instances['glossary'][$this->config->glossary])
-                || ((empty($this->config->globalglossary) && ($this->config->courseid != $this->page->course)))) {
+                || ((empty($this->config->globalglossary) && ($this->config->courseid != $this->page->course->id)))) {
             $this->config->glossary = 0;
             $this->config->cache = '';
             $this->instance_config_commit();