Duplicated WC variations in polylang

Hello,

I already wrote to you 6 months ago about problem with duplicated variations in woocommerce products. (https://wordpress.org/support/topic/duplicated-product-variations-in-woocommerce/) but you never gave me reply and help me with that. I will write it again:

We are using ERP system to manage products outside WordPress and because of that i needed to write plugin to import products and variations from ERP into Woocommerce. As you can see below I am using standard functions to create new variation for product:

private function insert_variation(){
    $attributes = Helper::get_variation_attributes($this->product_data['attributes']);
    $variation = new \WC_Product_Variation();
    $variation->set_sku($this->product_code);
    $variation->set_parent_id($this->parent_id);
    $variation->set_attributes($attributes);
    $variation->set_name($this->product_data['title']);
    $variation->set_manage_stock(true);

    $this->variation_id = $variation->save();

    $product = wc_get_product($this->parent_id);
    $product->sync($this->variation_id, true);
}

This is also how i create product for this variations:

private function insert_product(){
    $product = new \WC_Product_Variable();
    $product->set_name($this->product_data['title']);
    $product->set_sku($this->product_data['sku']);
    $product->set_status('draft');
    if($this->product_data['luxury']){
       $product->set_category_ids(array($this->assign_to_luxury()));
    }

    $this->product_id = $product->save();

    pll_set_post_language($this->product_id, 'pl');
    $this->create_translations();
}

And after I create product or variation I’m creating translations of this product by:

private function create_translations(){
    $languages = Helper::get_languages();
    $wc_apd = new \WC_Admin_Duplicate_Product();
    $translations = array('pl' => $this->product_id);
    if(!empty($languages)){
        add_filter( 'wc_product_has_unique_sku', '__return_false' );
        foreach ($languages as $lang){
            if($lang == 'pl') continue;
            $duplicated_product = $wc_apd->product_duplicate(wc_get_product($this->product_id));
            pll_set_post_language($duplicated_product->get_id(), $lang);
            $translations[$lang] = $duplicated_product->get_id();
        }
        remove_filter( 'wc_product_has_unique_sku', '__return_false' );
        pll_save_post_translations($translations);
    }
}

Polish version of products is default and I assign it right after creating product.

And here the fun begin… Products and variations are created correctly and saved as drafts. But after I change product description or other fields and then save it variations create their duplicates.

We are using:

• Woocommerce – in latest version (7.3)
• Polylang for WooCommerce – in latest version (1.6.3)
• Polylang Pro – in latest version as well (3.2.5)