Custom Post Type not Purging Properly

I am running a wordpress multi-site on nginx with varnish with multiple mapped domains.

I have w3 set up to work with varnish and have the option “Enable varnish cache purging” checked

Things seem to be running smoothy on pages and blog posts…with the exception of custom post types.

For some reason if a user on a sub-blog makes an update or creates a new post on page with a custom post type, if a user has previously visited the site page, or archive or looks for the new post they will not see the changes nor the post. However if a new visitor attempts to look at the same stuff they will see the new or edited content. Restarting the varnish fixes it so that the person who had previously visited the post can see the reflected changes…however that is not a solution.

Any ideas why this issue is occurring, is this a setup issue or a bug.

Thank you.

https://wordpress.org/plugins/w3-total-cache/