Paid Order Changed to Awaiting Payment

Hey guys

Just wondering if anybody else has had the unfortunate experience of this happening to them and know why and/or found a fix. We're running 2.2.5 on the problematic store.

A customer placed an order on my store last week and paid via the PSP SagePay. The payment was 100% successful (all security matched and passed checks OK) and the order appeared in the CS-Cart admin as 'Processing' - our default status for payments which are Paid, but not yet shipped. This customer completed the check-out as a guest and therefore has no customer account.

The customer called this morning to say she has paid for the order but got an e-mail last night with instructions on how to pay, as her order status was “Awaiting Payment”, after she tried to check the status online, but couldn't log in.

I checked the traffic statistics logs this morning to find the customer tried to access their order last night while the shop was closed. The customer tried to access the order via the link in the e-mail:

This store has the Order Status History addon installed, which confirms the order status was changed from Processing to Awaiting Payment at the exact time the customer attempted to access their order details.

What? Where? When? Why? How?