I have missing orders in Magento which were actually paid for without confirmation, nor an email and are absent in Magento back-end.
As a test I place an order and I don't see anything going on the last point of checkout. I think that something went wrong.
I check my store for new orders I check my emails but nothing. So naturally I place the order again as I think it wasn't processed. Second time it went through fine. Later I see on PayPal that I actually placed 2 orders and charged for two orders.
The database doesn't show the two only the second one. However in PayPal there are two order numbers (e.g. 1777587 and 1777588) and in the database just one (e.g. 1777588). Obviously the number is being generated by Magento given to PayPal to process but not being saved. Weird!
However it doesn't happen every time to every one but it happens 15% of the times lately. Thats not good people get charged twice or I lose orders.