Timed practice timer skips to 0:00
After entering my first answer in timed practice, the timer immediately skips to 0:00 and thus the lesson is ended. I tried a couple of times, also I refreshed my browser. Nothing helps. If I enter the first question correctly I do get 1 point awarded as usual. My computer hasn't switched to daylight saving time yet (that'll start in a few hours here in Europe), so that can't be it.
I'm running on Safari 6.1.2.