If you have Gift terms enabled on your application, it's possible to show a Redeem button in the footer of your Offer templates.
In order to remove it, you would need to go to Manage → Templates and remove the following code from your Offer template:
HTML
<div class="offer-redemption" ng-show="allowRedemption()">\n <table>\n <tr>\n <td class="title">\n <t>Did you receive a voucher?</t>\n </td>\n <td class="choose">\n <a ng-click="startRedemption()" external-event="piano-checkout-offer-click" class="button big fixed"><t>Redeem</t></a>\n </td>\n </tr>\n </table>\n </div>