magento 1.9.3.6 – Warning: Missing argument 2 & 3 for Varien_Simplexml_Config :: loadString () error in system.log

I get these errors in system.log. Magento 1.9.3.6

Warning: Missing argument 2 for Varien_Simplexml_Config :: loadString (), called in /home/patoys/public_html/app/code/core/Mage/Core/Model/Config.php on line 786 and defined in / home / xxx / public_html / lib / Varien / Simplexml / Config.php on line 507

Warning: Missing argument 3 for Varien_Simplexml_Config :: loadString (), called in /home/patoys/public_html/app/code/core/Mage/Core/Model/Config.php on line 786 and defined in / home / xxxx / public_html / lib / Varien / Simplexml / Config.php on line 507

I tried to debug them by adjusting the loadstring function in the config.php file:

public function loadString($string,$el,$filePath)
    {
        if (is_string($string)) {
            libxml_use_internal_errors(true);
            $xml = simplexml_load_string($string, $this->_elementClass);
            if (false === $xml) {
              //$errors = libxml_get_errors();
              echo "
";$filePath; die; } if ($xml instanceof Varien_Simplexml_Element) { $this->_xml = $xml; return true; } } else { Mage::logException(new Exception('"$string" parameter for simplexml_load_string is not a string')); } return false; }

Does anyone have any idea how other bugs can be fixed?