forum external function get_forum_discussion_posts returns incorrect userprofileurl

Create a course with several students/teachers with user pictures (test users created from MDK will do). Create a forum activity and add a discussion. Login with the created accounts and post a reply to the discussion. As admin, enable "Mobile services": Plugins ► Web Services ► Mobile Create a Token for the admin or any of the created users. Click on Site administration ► Plugins ► Web services ► Manage tokens On a terminal, enter the following curl command (replace the values in square brackets accordingly). curl 'http://[SERVER_URL_HERE]/webservice/rest/server.php?moodlewsrestformat=json' --data 'discussionid=[DISCUSSION_ID_HERE]&wsfunction=mod_forum_get_forum_discussion_posts&wstoken=[TOKEN_HERE]' --compressed | python -m json.tool Choose a post from the JSON data and copy the value for userpictureurl field and open it on a browser. Confirm that the displayed picture matches the user associated with the chosen post. Repeat the above step for the other forum posts. Edit user_picture::__construct() and change $needrec = false; to $needrec = true; (in or around line 218 of lib/outputcomponents.php). Run the above curl command on the terminal again. Choose a post from the JSON data and copy the value for userpictureurl field and open it on a browser. Confirm that the displayed picture matches the user associated with the chosen post. Repeat the above step for the other forum posts.