ps_product_group_cache is not updated automatically on product category change

[Namor Esther]

Hello,

My Prestashop version is 1.7.2.

I'll try to be as clear as I can. I have created many reductions for many client groups on my Prestashop. Those reductions are connected with product categories. But, when I change the category of a product, its reduction doesn't change, I have to go on client groups page and save each group. I have checked database and I found that was because ps_product_group_cache table was not updated on category change.

I think about a solution, but I don't know if it could work : I've found that the update of this table was made in "classes/GroupReduction.php", in update() method, maybe I could call it with a button to update all reductions in one click.

Here is the method update() and _updateCache() in "classes/GroupReduction.php" :
 

	public function update($null_values = false)
    {
        return (parent::update($null_values) && $this->_updateCache());
    }

	protected function _updateCache()
    {
        $products = Db::getInstance(_PS_USE_SQL_SLAVE_)->executeS('
            SELECT cp.`id_product`
            FROM `'._DB_PREFIX_.'category_product` cp
            WHERE cp.`id_category` = '.(int)$this->id_category,
        false);

        $ids = array();
        foreach ($products as $product) {
            $ids[] = $product['id_product'];
        }

        $result = true;
        if ($ids) {
            $result &= Db::getInstance()->update('product_group_reduction_cache', array(
                'reduction' => (float)$this->reduction,
            ), 'id_product IN('.implode(', ', $ids).') AND id_group = '.(int)$this->id_group);
        }

        return $result;
    }

Thanks for answers,

Namor.