I'm using WPTouch 18.104.22.168, and the latest W3TC.
Sometimes, even when visiting my site with Firefox or IE10, some of my blog posts will be displayed with the mobile theme even though I'm on the desktop.
If I disable WPTouch, the mobile theme is still used for those articles which lead me to think that this might be a caching issue, an incompatibility with W3TC, but the rest of the time everything works fine.
Any ideas how to prevent this from happening? Disabling W3TC isn't an option.