Data error in Analytics – The server provided an invalid response.

Hi! I have a function in functions.php which cause an error in Site Kit Summary:
Data error in Analytics – The server provided an invalid response.
Screenshot: https://prnt.sc/tTBVFFdjJ71s

Function has is_admin() check, so I don’t understand how can it cause a problem with Site Kit Summary , please help me, thx.

Function:

//==============================================================================
//	Disable payment gateway "Cash on delivery" if there's specific ACF product in cart
//==============================================================================
add_filter('woocommerce_available_payment_gateways', 'filter_gateways_byacf');

function filter_gateways_byacf($gateways) {
	// Make sure it's only on front end
    if ( ! is_admin() ) {
		
		// Check if WooCommerce is active
		if (!function_exists('WC')) {
			return $gateways;
		}

		// Get the current cart
		$cart = WC()->cart;

		// Loop through cart items
		foreach ($cart->get_cart() as $cart_item) {
			// Get the product ID
			$product_id = $cart_item['product_id'];

			// Get the supplier value for the product
			$supplier = get_field('supplier', $product_id);

			// Unset "cod" gateway if supplier is "Brain"
			if ($supplier != 'Brain') {
				unset($gateways['cod']);
				break; // Stop the loop after unsetting the gateway
			}
		}

		return $gateways;
	}
}