diff --git a/nag/lib/Driver.php b/nag/lib/Driver.php
index c9a85d6f5e1..18218fb27d9 100644
--- a/nag/lib/Driver.php
+++ b/nag/lib/Driver.php
@@ -217,6 +217,7 @@ public function modify($taskId, array $properties)
          * because this might be a recurring task, and marking the
          * task complete might only shift the due date to the next
          * recurrence. */
+        $task_completed = $task->completed;
         if (isset($properties['completed']) &&
             $properties['completed'] != $task->completed) {
             if (isset($properties['recurrence'])) {
@@ -237,6 +238,10 @@ public function modify($taskId, array $properties)
 
         $this->_modify($taskId, array_merge($task->toHash(), $properties));
 
+        // Must persist the original completed value so we can detect the
+        // change when notifications are sent.
+        $task->completed = $task_completed;
+
         $new_task = $this->get($task->id);
         $log_tasklist = $this->_tasklist;
         if (isset($properties['tasklist']) &&