See the thread here:
https://www.mobileread.com/forums/sho...=157772&page=4
You'll have to either:
1. Wait for Kobo to actually fix the problem. (wouldn't hold my breath at this point.)
2. Demand a refund and buy the book from somewhere else. (Don't settle for store credit. There are consumer protection laws against selling known deffective stuff.)
3. Remove DRM and fix the book yourself. On most of the affected books, that should be a simple as remving the kobo.css and kobo.js files from the e-book. It's a bit more complicated if the book does not include it's original css anymore. Jwolf has posted more thorough instructions that will not only correct the problem but create a valid epub that will pass validation checks.
4. Just pirate the thing.