I have been submitting tickets for this issue for a year, with no response, other than a claim in the updates to have fixed it, but it still there as of 2.8.2. Here's the scenarios where we see it happen.
Our events are paid for over time, so the initial registration is just a minimal deposit (partial payment) so user return to our site to log in and make additional payments in the User Panel, using the "Pay Now" link. If a user, follows the steps but then stops on the submit payment page, and hits the browser back button, they get an error page with the option of "Next Step" If they hit next step, a duplicate registration is created, showing that both the original and the duplicate have made a payment. A payment confirmation email also goes out, but no payment is sent to the payment gateway, so no money is actually every exchanged.
So the end result is: A new registrant that does not exist, and two payments that do not exist.
Try to make a payment on the original registration, and you get another error message, and that registration suddenly becomes "free."
In testing the First Time Registration payment page and hitting the back button, I was able to create Duplicate registrations of the same user in one session. The credit card was charged, I think for each registrant, but in returning to register again using the same User ID, the original registration disappeared, even though a payment had already been processed on its behalf. In another test of the browsers back button, the base trip cost was removed, but the registrant was billed only for the fee field I created for that event.
Note, I have only found these errors using the "back" button in Firefox browser. I could not replicate it in Safari or Chrome.
It's not that often that it happens to our clients, but it's a pretty grave problem, when the potential is there to be overcharged, or to create false registrations and false payments and not really be charged at all.
I encourage everyone out there to look out for these duplicate records. Whenever we have 2 payments from the same person come in at the exact same moment, we've learned to see it as a red flag and double check DT Register records with our Merchant Services $ records for irregularities. It's professionally embarrassing to tell a client, I know you got a payment confirmation email from us, but check your credit card statement and you'll see you weren't actually charged.
I also encourage everyone to keep reporting it here and in the tickets, as I've done. I've been reporting it for a long time now, but have largely been overlooked, despite my thorough explanations and urgent pleas for a fix. Perhaps dthadmin thinks these aren't legit issues, or its an isolated issue.
