I've observed a strange behavior whereby a customer managed to place three orders in quick succession which had the same order numbers.
Each order was based on the same quote_id which in turn represents the correct reserve_order_id value. The orders were placed at these times:
- 2014-12-15 16:41:11
- 2014-12-15 16:43:10
- 2014-12-15 16:46:39
The first order had the order confirmation email sent to the customer, but the second and third orders did not.
How did each order have the same order number even though the sales_flat_quote table seemingly correctly set the value for reserve_order_id?
P.S. I've noticed this same issue pop up about 2 – 3 times a month, so very rarely (upwards of 800 orders are placed monthly).
Edit 1: As soon as a customer clicks the Place Order button during checkout on our website, the button vanishes & the following loading symbol is displayed:
As such this cannot be as a result of the customer repeatedly hitting the Submit Order button.
Best Answer
I've seen something like this before where a shop was a bit slow on redirecting the customer from the checkout to the Payment portal.
The user clicked the submit button multiple times which caused several orders to be created. So there isn't really a technical issue here, more an user UI issue.
I would advice to first of all call the customer and ask him what happened and maybe display a clear loader or even hide the submit button after the user has clicked it in the checkout