I am following the instructions here:
I have created a custom views folder in my site - and copied across the variants and web.config from the views folder.
I have added dummy text and markup to the promo.cshtml file.
In my tenant settings I have added a path to my custom views folder.
I have restarted IIS, and added a new page with a promo component to it - but do not see the markup that I modified. I don't see any errors in the main log file.
Based on the documentation I would expect it to load my overridden view.