Originally Posted by Adam1222

This is not generally how it works. Often, the reservation will reflect both nights at their full rate and the second night will be zeroed out when you arrive at the property, as that's when the certificate is redeemed.

Originally Posted by demue

Exactly, second night is free. This can work to your advantage or against you depending on which night is cheaper. Halving both nights is not correct an even if price would be the same when both have same rate, it can lead to problems with the stay posting as qualifying as well (in some cases) as two nights at supposed 50% discount can trigger the heavily discounted rate issue (>30% off regular rate) and the entire stay could post as non-qualifying and later require manual intervention and promos may not track correctly and all that fun stuff. YMMV