There is a new dev version out version 4.0.237.0 which when I download this newest version the lock out of the dashboard stopped so yes it was a Google chrome issues on how it accepted cookies.
you can find the 4.0.237.0 version of Google chrome here http://dev.chromium.org/getting-involved/dev-channel
Please note staff does NOT support Beta versions of browsers here at WP.com so if you are having issues with the browser and WP your best bet is to uninstall the browser and revert back to a stable version then wait for a more stable beta release to be released.