The same thing happened for me with the latest update. I thought it was the webhost (and truth is, their support wasn't good or they would have picked up on the problem) and after three days of downtime I switched to a new host for the first time in two years. We have a busy site and couldn't risk losing all our readership.
The new host figured out that the issue was coming from the plugin, so in the meantime I have it deactivated. Like those above me, I never saw an issue because it only appeared for those who weren't logged in.
The problem is that we really rely on the plugin to help with our server load. The plugin is amazing and it helps us leverage memcached, APC, and Amazon Cloudfront. So I really hope this gets ironed out because I don't want to use WP Super Cache if I don't have to. That plugin just doesn't compare to W3 Total Cache.