I don’t really get what you mean with template overrides. I have a clean installation of the latest versions of Canvas/Scholar and WooCommerce. Also the framework and WordPress is up to date. No modifications has been done to anything that could affect how the coupon sum is displayed or calculated.
I tried it out with Twenty Twelve with the exact same result.
https://www.dropbox.com/s/q7ijwvafp33gnkg/weird.png?dl=0
So what to do?