Hi,
It could be that the customer clicked on "finish" at the end of the checkout, went to the payment gateway, and there clicked on "cancel", went back to the checkout, and clicked on "finish" again before doing the payment.
In that case, you would get a "created" order and a "confirmed" order just after. It could well be in the same minute.
We have of lot of these on our website. For example, we got one today:
monosnap.com/file/r7iCXXP6qDCIDEIELNCnESveLutUae
You can see the customer did a lot of back and forth before changing the payment method and finishing the payment with the last order.
So it's highly possible that it's nothing you can do on your end. Just the customer having trouble with your payment gateway (because of the 3Dsecure, or the PayPal account), or he just wants to confirm or change something.