I don't think the clocks are keeping good time !
When i play bullet chess sometimes i lose by 25 sec.
If you take a close look at the clocks you will see that the clocks are off.
The screen will dim and then the other player will pick up 20 sec.
At the end of a game the computer will not end the game.
play will run with no time on the clock.
Thanks Doublebruce