As per this post with both redactor.convertDivs and redactor.replaceDivs settings set to no does the trick. As this keeps coming up regularly I’ve just added it to the Redactor FAQs, something we should definitely do more often 
As per this post with both redactor.convertDivs and redactor.replaceDivs settings set to no does the trick. As this keeps coming up regularly I’ve just added it to the Redactor FAQs, something we should definitely do more often