When I tap on the ''Log Out'' button of Facebook, I get this message - BAD REQUEST - Your browser sent a request that this server could not understand.
Just tried on my X8 and it logged out fine. Have you downloaded the Facebook for Android app from the market to see if this helps? If you have done this already then try Settings>Applications>Manage Applications and then find Facebook for Android and clear data/clear cache/uninstall updates and maybe even force close it from there to see if it then asks you for a log in next time you access the app.
Just tried on my X8 and it logged out fine. Have you downloaded the Facebook for Android app from the market to see if this helps? If you have done this already then try Settings>Applications>Manage Applications and then find Facebook for Android and clear data/clear cache/uninstall updates and maybe even force close it from there to see if it then asks you for a log in next time you access the app.
