PayPal IPN not setting payment status – stays "Incomplete Sale"

Version information and settings:
WordPress: 3.4.2
WP e-Commerce: 3.8.9.2

PayPal Payments Standard 2.0
Account Type: Live Account
IPN: Yes
Send shipping details: No
Address Override: No

Hello,

Under Dashboard –> Store Sales –> Status, it now defaults to “Incomplete Sale” even though the payment went through. Up until a little over a week ago, once the payment cleared, it would change to “Accepted Payment,” and email the user regarding the digital download purchase. Nothing has changed on the server, or with the PayPal account.

I do see the IPN pingback from PayPal:

02 # grep 'PayPal IPN' access_log
173.0.81.1 - - [02/Feb/2014:06:11:15 -0500] "POST /index.php?wpsc_action=gateway_notification&gateway=wpsc_merchant_paypal_standard HTTP/1.0" 200 19 "-" "PayPal IPN ( https://www.paypal.com/ipn )"

As nothing has changed, I’m at a loss as to where to check. I have looked through previous support posts, and have tried the changes that were suggested, but to no avail.

Please advise.

Thank you preemptively.

Cheers,
Nathan Zachary

https://wordpress.org/plugins/wp-e-commerce/