Front-office Prestashop 1.7 : Sélection d’une déclinaison impossible

private function getIdProductAttribute($useGroups = false)
    {
        $requestedIdProductAttribute = (int) Tools::getValue('id_product_attribute');

        if ($useGroups === true) {
            $groups = Tools::getValue('group');

            if (!empty($groups)) {
                $requestedIdProductAttribute = (int) Product::getIdProductAttributesByIdAttributes(
                    $this->product->id,
                    $groups
                );
            }
        }

        if (!Configuration::get('PS_DISP_UNAVAILABLE_ATTR')) {
            $productAttributes = array_filter(
                $this->product->getAttributeCombinations(),
                function ($elem) {
                    return $elem['quantity'] > 0;
                }
            );
            $productAttribute = array_filter(
                $productAttributes,
                function ($elem) use ($requestedIdProductAttribute) {
                    return $elem['id_product_attribute'] == $requestedIdProductAttribute;
                }
            );

            if (empty($productAttribute) && !empty($productAttributes)) {
                return (int)array_shift($productAttributes)['id_product_attribute'];
            }
        }

        return $requestedIdProductAttribute;
    }