gift vouchers not working in oc 2

hi guys

i have just setup oc2 and added all my products but i am having some weird issues with gift vouchers.

a customer can buy one and it takes their paypal payment and the receipient receives the code.

but when the other person tries to use the voucher code it says

Warning: Gift Voucher is either invalid or the balance has been used up!

but this is wrong. when i check the voucher it says it is valid from the admin settings,

i have read a few forum posts about saying the order needs to be complete before the voucher can be used but when i check under orders it says complete for the voucher purchace.

can anyone help? thank u in advance