The mb-user-profile/inc/class-mb-user-profile-user.php file is using the wrong action name within the save() function. The After save action is set to "rwmb_profile_after_save_post" instead of "rwmb_profile_after_save_user".
public function save() {
do_action( 'rwmb_profile_before_save_user', $this );
if ( $this->user_id ) {
$this->update();
} else {
$this->create();
}
do_action( 'rwmb_profile_after_save_post', $this );
return $this->error;
}
This is true for both the single extension and AIO.