Order corruption

Hi, I'm using version 1.3.8a with the PayPal std and HSBC payment modules. I've been running these for ages and there has been no upgrades or changes made recently.

I occasionally (i.e. once every few months) get order problems where the details that appear on the orders page bear no resemblance to what has actually been ordered. I have just had two orders received.

The first received at 10.06.05 on 19th Feb, payment made through HSBC for £4.55 (Customer A).

The second at 10.12.21 on 19th feb, payment through PayPal for £3.32 (Customer B).

The correct amount has been taken by both PayPal and HSBC, but the order details in Admin show two new orders both for Customer A, but the products and value of Customer B.

Both customers have emailed me to say their email confirmation includes the other persons orders and to confirm what they had ordered. If it wasn't for that, I wouldn't know who had ordered what.

Please could someone help shed some light on this and let me know how I can solve the problem. It may not happen often, but when it does, it causes me loads of problems.

Thanks in advance