why show payment method:Gift Certificate/Coupon in my website?

I'v never configure the Gift Certificate/Coupon payment method in my website,but several order show payment method:Gift Certificate/Coupon today.
I couldn't find the cause of the problem,who can help me?

thanks very much.

What are your settings for those items in Admin - Modules - Order Total ?

I'v install ot_coupon\ot_gv\ot_shipping\ot_subtotal\ot_tax\ot_total in admin->modules->order total,and i had removed the ot_gv,but payment method:Gift Certificate/Coupon still appear in order

Has anything more been found out about this issue?

I am having the same problem, always with big $ value orders. After the first time it happened I disabled the GV module and it has happened again. Unfortunately I am unable to get into the SSL logs to see what went on.

I am using Ver 1.3.9h an have the following payment mods installed:
CEON CC - (switching soon to banks payment system)
Phone/Fax cc details
Bank deposit
Cheque/Money order

Date Purchased: Friday 22 July, 2011
Payment Method: Gift Certificate/Coupon

and there is no cc details collected, it just looks like an order that has been paid for wholly by a GV or coupon.

We do have a coupon running at the moment, but it wasn't running when the first instance happened after upgrading. Both customers were new customers and would not have known about our 7.5% discount coupon (that we are aware of).

I have just spoken with the customer who placed the order to be paid for by GV and she told me that she selected the Installment Plan (sorry, forgot to mention we had that as a payment option). So this could be where the problem lies - maybe?