Same problem here. Actually, even after purging the cache, deactivating and removing the w3 plugin the problem was still there and the developer had to restore the theme config file for things to work.
I am using siteground managed hosting and tried to use w3 cause SG caching plugin by Siteground did not work too. They investigated and told me that no conflict with any plugin and the only thing they are suspicious about is the theme.
I am not sure what is the problem with your theme and caching?!