On Mac OS X most recent version of Firefox it sometimes shows the shape to the right as entirely darkened and other times not when I type "inconsequential". Any reason for this?
I'm guessing that the server got too busy to serve a request, either the last request, or any previous one, so that you broke the token chain. Another possibility could be a bug with the timing of events, such that it doesn't realize the field has changed.
The author seems to be lurking around here, maybe he'll have a better idea.