Here the things you may or may not noticed about clocks in any version of the show.
UK[]
Since in Series 9, the clock doesn't seem to hit to 0:00 whenever it was supposed to be, despite a chaser actually winning. That's does not actually stay that long if a chaser answers it wrong or does not answer at all. The last ever time the clock hits to 0:00 was on 26th June 2015 when Mark Labbett (The Beast) answers a question with the answer of Switzerland in 0:00, start the "S" sound before the buzzer and finishes with his answer.
For examples, Peter and Warjinder £60,000 final chase with The Governess where the clock slowed down at the last second, Claire, Mike, and Lyn's final chase with The Dark Destroyer when you may notice the lights on the C flashing blue, indicating that, had the Chaser answered wrong or a millisecond later, he would've run out of time, and Amy Walsh, Matthew Wolfenden and Mark Charnock's final chase with The Sinnerman where you see the on-screen clock stops at 0:01, but klaxon goes off and the studio goes blue (indicating a team win). It's commonly accepted that if an answer is started in time, it is used. Perhaps the studio crew and the adjudicators had a mismatch?
Croatia[]
In the Croatian version of the show, when the clock starts it runs 2:00 to 1:59 for half a second early and klaxon plays and the clock disappears for half a second late after the clock hits to 0:00. This is just like our Apple iPads, iPods, or iPhone when you go to timer and for no matter how much time, you press start and it does the same thing.
The clock no matter if the chaser wins or not, klaxon always plays on 0:00, and then it disappears (until Season 6). Because klaxon didn’t play nor the clock disappeared on 11th February 2015, 1st January 2017, 30th May 2017, 23rd November 2019, and 29th November 2019, the chaser won on 0:01, not 0:00. So far now, there has been three 0:00s in the Croatian version of the show, leaving the UK's record of 8 0:00s.
The clock stops at what it said was on 0:00, but really it stops at 1 second. This happened during Mirko Miočić's final chase on 20th May 2014 and Morana Zibar's final chase on 30th January 2017.
This was until the sixth season the clocks starts and ends normally like every other version of the show.