I have a UK based website running Magento 1.4.0.1 and recently added PayPal Payments Standard as a payment option. It works as expected for the most part, but recently I've had 2 overseas orders come through that haven't been charged shipping (one to Germany and one to Sweden).
When viewing the orders in the backend, Magento seems to think that shipping was charged, but when PayPal is checked, it confirms that no shipping was charged. Obviously, the figure charged in PayPal is the Magento figure minus the shipping figure.
I have absolutely no idea why this is happening, but my client is worried about it understandably. This question has been asked before but there were no replies.