I actually experienced a bug related to this yesterday because I have a cPanel license with buycpanel.com. They normally charge my credit card every month, but I strangely got a late notice. So, I login (to whmcs) and click the card on file, enter the CVV and go to pay, and it says there is an error.
So I contacted them and asked if it was related to the whmcs patch, and they responded with..