Not for the first time, my opponent's clock went from just 10 seconds remaining to 1 minute (lol), then from 4 seconds it went up to something like 15. The 'seconds' on his clock seemed to last 3 or even 5 seconds while mine were going really fast. Then, when he ran out of time i.e. 0,0 seconds the match was not awarded to me but just after the third time it happened.

Is it just a bug(s) or people can really cheat with the clock?

What do you think, any experiences to tell?

I think its supposed to be like this. Something to do with lag maybe?

Lag

It could well be the lag then as he lost the connection about four times during the game.

Had a game recently where I was up on time, impending mate, and my opponent disconnected. While I'm waiting for him to re-connect, his clock runs down to zero. I stuck around for a few minutes then closed the board out, only to find that I was charged with the loss for abandoning the game. lol. Still working out the "bugs", I suppose.

no-no...I think it was lag or disconnecting from the game because it is hard to do something like cheating or using a third party software but I think the bug's factor can not be considered as the main factor also, so I think there is only two factors that cause this time problem: lag and bad connection!

For starters there's no way to cheat with the clocks.

As others have mentioned, it's probably the result of clock corrections for lag which is actually something that's designed into the application, however that does seem like fairly severe lag.  One of you or your opponent (or possibly both) must have had an exceptionally bad connection for such large adjustments to have occurred..