[tartaglia]

First, I must say that I am a believer in QT and their XC product. I have been working with them since 2006. I pay for their support subscription service.

The following is posted ONLY to educate my fellow X-Carters about a BUG that has been confirmed by QT but has yet to be fixed and which could be problematic to a company and their reputation without their knowledge. The QT Maintenance Team is working on a resolution but has not released one yet.

For full disclosure I run XC 4.5.4 Gold+ w/ X-Payments.

Summary: If a customer attempts to use a XC Gift Certificate to partially pay for a purchase, they could find themselves in a unrecoverable situation and be unable to complete their order. This is significant because selling Gift Certificates is good business for merchants however if word gets out that they can't be redeemed reliably, sales of GC are likely to drop signifcantly.

Scenario (Repeatable steps):
1. Customer gets to the OPC page, enters their personal details, selects a shipping method and enters and submits their GC code for application against their order total.
2. When the order total is greater than the present value of the GC (this is a preferred scenario for merchants!), XC advises the customer that they must pay the remaining balance using another GC or Payment Method.
3. The customer selects to use the Credit Card payment method, and the XP iframe loads with fields for the credit card data.
4. At this point, should the customer choose to modify either any of their personal details (billing address, etc.) or modify the selected shipping method, they are presented with an non-human-readable error code in the payment iframe and they are unable to continue with their order.

As a merchant you may never know this is happening, unless a customer complains in detail.

In our case we were VERY much looking forward to promoting the sale of GC on our site for this holiday season. But when we learned of this bug we could not in good conscience do so for fear of frustrating our customers. I hope this post helps others.

The bug was confirmed by QT on Oct 18, 2013 on XC versions up through 4.6.1.