Error msg PHP Warning: Undefined array key “product_cat”

Hi, I have a lot of error messages like this one:

AH01071: Got error ‘PHP message: PHP Warning: Undefined array key “product_cat” in [***] /wp-content/plugins/product-quantity-for-woocommerce-pro/includes/class-alg-wc-pq-core.php on line 1382

It’s here:

function set_quantity_input_args( $args, $product ) {
		global $wp_query;
		
		$category_name = $wp_query->query_vars['product_cat'];

Can you help me solve it?

Thanks!

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