PHP Fatal error Call to a member function get_type() on boolean

Had this on my debug.log today [WP_DEBUG=true]:

PHP Fatal error: Uncaught Error: Call to a member function get_type() on boolean in \plugins\woocommerce-admin\includes\data-stores\class-wc-admin-reports-coupons-data-store.php:362

Reading the offending like it becomes apparent the false == wc_get_order() case isn’t being handled:

$order = wc_get_order( $order_id );

// Refunds don't affect coupon stats so return successfully if one is called here.
if ( 'shop_order_refund' === $order->get_type() ) {
	return true;
}

In other parts on your code you do such check like this:

if ( ! $order ) {
	return -1;
}

So this block of code shall become like this:

$order = wc_get_order( $order_id );

if ( ! $order ) {
	return -1;
}

// Refunds don't affect coupon stats so return successfully if one is called here.
if ( 'shop_order_refund' === $order->get_type() ) {
	return true;
}

Searching your code for other instances of wc_get_order we can see the same potential issue here:

\plugins\woocommerce-admin\includes\data-stores\class-wc-admin-reports-taxes-data-store.php line 314:

public static function sync_order_taxes( $order_id ) {
	global $wpdb;
	$order       = wc_get_order( $order_id );
	$tax_items   = $order->get_items( 'tax' );

and here:

\plugins\woocommerce-admin\includes\api\class-wc-admin-rest-reports-controller.php line 189:

$order = new WC_Order( $order_id );

if ( 'shop_order' !== $order->get_type() ) {
	return $order_id;
}

HTH.