It could be an issue if you use the certificate in the same hotel both times. This is anecdotal so I really don’t know how it would work out for others, but a friend was in a similar situation: used the weekend cert at an IC in Europe Summer 2022. The cert remained in the account and was used again to book a weekend 8 months later at the same IC. At check out, they were charged for both nights because the system recognized that the certificate had ready been used for that 12 month period. I didn’t ask for more detail of how the conversation with the front desk at check out went. In the end, I understood they had to pay, no way around it.