Django CSRF cookie not set in several browsers

Question

I have very strange problem - CSRF cookie not set on some of clients browsers. What could it potentially be?

All needed middleware is enabled, and as I said above, problem appears only on very small count of machines, although another Django-powered sites work well there.

Answer 1

The problem didn't solved in usual way, so I refused from cookie-based CSRF-protection and get session-based instead: https://github.com/mozilla/django-session-csrf.