Undefined property: Invoices::$ServiceInvoices on line 1116 in C:\wamp64\www\blesta\public_html\app\models\invoices.php

Printing Stack Trace:
#0 [internal function]: UnknownException::setErrorHandler(8, 'Undefined prope...', 'C:\\wamp64\\www
b...', 1116, Array)
#1 C:\wamp64\www\blesta\public_html\vendors\monolog\monolog\src\Monolog\ErrorHandler.php(164): call_user_func(Array, 8, 'Undefined prope...', 'C:\\wamp64\\www
b...', 1116, Array)
#2 C:\wamp64\www\blesta\public_html\app\models\invoices.php(1116): Monolog\ErrorHandler->handleError(8, 'Undefined prope...', 'C:\\wamp64\\www
b...', 1116, Array)
#3 C:\wamp64\www\blesta\public_html\app\controllers\admin_clients.php(5701): Invoices->appendServices('6929', Array)
#4 C:\wamp64\www\blesta\public_html\app\controllers\admin_clients.php(5580): AdminClients->createService(Array, Array)
#5 C:\wamp64\www\blesta\public_html\app\controllers\admin_clients.php(4573): AdminClients->processServiceStep('confirm', Object(stdClass), Object(stdClass), Object(stdClass))
#6 C:\wamp64\www\blesta\public_html\vendors\minphp\bridge\src\Lib\Dispatcher.php(143): AdminClients->addService()
#7 C:\wamp64\www\blesta\public_html\index.php(21): Dispatcher::dispatch('/blesta/public_...')
#8 {main}

This code needs to be added at the start of the method:

        if (!isset($this->ServiceInvoices)) {
            Loader::loadModels($this, ['ServiceInvoices']);
        }

This bug was introduced by CORE-2167