Coupon used more than once

Got a big problem with vouchers in OpenCart v1.5.1.3 - customers are able to be use the same coupon/voucher more than once although I have set

"Uses Per Coupon"
and
"Uses Per Customer:"

both to "1". Makes no difference if it's the same customer or a new customer, it doesn't seem to be recorded that it's been used already.

Can any one help asap please!

Thanks

EDIT: Just noticed if edit any coupon that's been used and click on Coupon History nothing is recorded if that helps!
EDIT 2: Also, the coupon code is shown on the invoice!

It is important that I get this fixed ASAP. I am willing to pay for anyone that can fix it for me, please PM me. Thanks

Same prob did anyone PM you with a fix?

Thanks, John

Daniel informs me this is fixed, but its not in my OC 1.5.1.3 so if anyone can advise me of the fix it would be much appreciated?

Many thanks, John

I'm having the same issue. I'd happily pay for a fix.

Hope to hear from someone . . .