Experimental improvement:

classes/course_completion/conditions/course_completed.php

@@ -30,6 +30,7 @@
 use completion_info;
 use core_completion\progress;
 use local_adele\course_completion\course_completion;
+use local_adele\learning_path_update;
 
 defined('MOODLE_INTERNAL') || die();
 
@@ -148,7 +149,8 @@ public function get_completion_status($node, $userid) {
         }
         $isinbetween = false;
         foreach ($courses as $courseid) {
-            $course = get_course($courseid);
+            $course = learning_path_update::get_course($courseid);
+            // $course = get_course($courseid);
             $completed = false;
             if ($course->enablecompletion) {
                 // Get the course completion instance.

classes/learning_path_update.php

@@ -47,6 +47,26 @@
  * @license    http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  */
 class learning_path_update {
+
+    /**
+     * All courses
+     * @var array
+     */
+    public static $courses = [];
+
+    /**
+     * Return single course from id
+     *
+     * @param int $courseid
+     */
+    public static function get_course($courseid) {
+        if (!isset(self::$courses[$courseid])) {
+            $course = get_course($courseid);
+            self::$courses[$courseid] = $course;
+        }
+        return self::$courses[$courseid];
+    }
+
     /**
      * Observer for course completed
      *