diff --git a/backup/moodle2/restore_stepslib.php b/backup/moodle2/restore_stepslib.php
index b3d5322f70d..149f606ce46 100644
--- a/backup/moodle2/restore_stepslib.php
+++ b/backup/moodle2/restore_stepslib.php
@@ -485,6 +485,9 @@ class restore_gradebook_structure_step extends restore_structure_step {
         // Freeze gradebook calculations if needed.
         $this->gradebook_calculation_freeze();
 
+        // Ensure the module cache is current when recalculating grades.
+        rebuild_course_cache($this->get_courseid(), true);
+
         // Restore marks items as needing update. Update everything now.
         grade_regrade_final_grades($this->get_courseid());
     }
diff --git a/lib/grade/grade_item.php b/lib/grade/grade_item.php
index 60edaf60b92..769f69dfd3c 100644
--- a/lib/grade/grade_item.php
+++ b/lib/grade/grade_item.php
@@ -2495,8 +2495,22 @@ class grade_item extends grade_object {
      */
     public function get_context() {
         if ($this->itemtype == 'mod') {
-            $cm = get_fast_modinfo($this->courseid)->instances[$this->itemmodule][$this->iteminstance];
-            $context = \context_module::instance($cm->id);
+            $modinfo = get_fast_modinfo($this->courseid);
+            // Sometimes the course module cache is out of date and needs to be rebuilt.
+            if (!isset($modinfo->instances[$this->itemmodule][$this->iteminstance])) {
+                rebuild_course_cache($this->courseid, true);
+                $modinfo = get_fast_modinfo($this->courseid);
+            }
+            // Even with a rebuilt cache the module does not exist. This means the
+            // database is in an invalid state - we will log an error and return
+            // the course context but the calling code should be updated.
+            if (!isset($modinfo->instances[$this->itemmodule][$this->iteminstance])) {
+                mtrace(get_string('moduleinstancedoesnotexist', 'error'));
+                $context = \context_course::instance($this->courseid);
+            } else {
+                $cm = $modinfo->instances[$this->itemmodule][$this->iteminstance];
+                $context = \context_module::instance($cm->id);
+            }
         } else {
             $context = \context_course::instance($this->courseid);
         }