I pre-moved yet ran out of time

This game:

I pre-moved Kc3 and it actually showed up on my screen, but it didn't register and I lost on time. How can you have time left then spend exactly 0 and run out? I mean every single move there's a delay before the timer starts ticking to account for latency, so that can't be it...

You can't post in the forums yet. Play some games!