Quite possibly - the checks against automated attacks probably look for protocol trickery, which in some cases will be difficult to distinguish from a flaky client.
If it happens on a different network connection, we should probably raise it with CF.
It was the homepage (http://www.lfgss.com) via a bookmark in Chrome 34 on Windows 7.
We're experiencing some issues with our internet in the office at the moment. Could that have triggered it?
It's happened again since, just now, when trying to move from the homepage to my following page.