Caching less files when using dotless not working

I used Yet Another "Add LESS to your ASP.NET MVC Project" Post tutorial to set up dotless on my ASP.NET MVC 4 web application.
Everything seems to be working fine except the caching.
I have this dotless options in my Web.config:
<dotless minifyCss="false" cache="true" web="false" /> Dotless behavior is following:
When I launch my web application with compilation debug="false", the LESS files are presented as a bundle with the long hash identifier in the URL, etc. Thie resulting CSS file is cached (first request results in HTTP 200, other requests result in HTTP 304).
But when I am using compilation debug="true", the LESS files are added to the HTML as individual compiled CSS files. ...