Bug blocks the displaying of minicart in single product

I have an ecommerce with this plugin installed. It works but gives also a bug, it blocks the displaying of mini cart in the single product page. See here: https://fratellicarbone.it/prodotto/quattro-lattine-da-5-litri/ I studied the plugin code and I found a function which could cause the issue. That’s the function: add_filter( 'woocommerce_is_checkout', [ $this, 'woocommerce_is_checkout' ] ); //in the __construct() /** * Fake woocommerce checkout page. * * @param bool $is_checkout Is checkout page?. * * @return bool */ public function woocommerce_is_checkout( $is_checkout ) { if ( is_product() ) { return true; } return $is_checkout; } If I deregister it, the plugin seems work fine and also the minicart starts again to work. So Anyone can tell me more about this function? I can’t find on google any useful info about the woocommerce_is_checkout filter, and I can’t figure out why this function would block the mini cart. The page I need help with: [ log in to see the link]