Timed practice - 44.1 years remaining
I have come across an error (presumably some kind of integer overflow bug) in the software (browser version) whereby the "time remaining" in timed practice cycled round to an impossibly large number. When I last checked it was sitting at 23210794:29 - over 44 years! (It had been a few minutes since the error happened.)
I have since exited the timed practice and and tried again, and (predictably) the error hasn't persisted. I'm not too bothered about the lost score (I only had 2 at the time anyway), so this isn't really troubleshooting, but I thought you should be aware of the issue. I did search for other threads on this issue but didn't find anything; my apologies if you are aware of it already.
If it has any bearing on the issue, the task at the time was one of those "say this phrase into your microphone" tasks. Other than that there was nothing remarkable about it. I'm running Firefox 28.0 (which is available via the beta update channel - the current stable Firefox release is 27.0.1 I think) and the current version (184.108.40.206) of flash player, although I suspect the error is more likely to be server-side.