We are using Varnish and Pressflow (v6.30). Every time we flush cache in Drupal, we encounter problems where browsers can not get requested CCS/JS aggregate files as they do not exist. We have found that if we flush Drupal cache and then immediately flush varnish cache, problem is fixed.
Anybody else had this issue? And is there a module (purge or similar) which automatically handles Varnish flush cache with Drupal cache?