diff --git a/course/classes/category.php b/course/classes/category.php
index 1a12b9b8c52..8a546a7ea62 100644
--- a/course/classes/category.php
+++ b/course/classes/category.php
@@ -629,10 +629,9 @@ class core_course_category implements renderable, cacheable_object, IteratorAggr
         }
 
         // Delete theme usage cache if the theme has been changed.
-        if (isset($data->theme)) {
-            $oldcategory = $DB->get_record('course_categories', ['id' => $data->id]);
-            if ($data->theme != $oldcategory->theme) {
-                theme_delete_used_in_context_cache($data->theme, (string)$oldcategory->theme);
+        if (isset($newcategory->theme)) {
+            if ($newcategory->theme != $this->theme) {
+                theme_delete_used_in_context_cache($newcategory->theme, (string) $this->theme);
             }
         }