I asked this in my post last week before the update but we had no enough info.
Yesterfay after some of my clanmates played war we noticed the deck reset 2 hrs after war starts and I sended clan message to tell them to no play war and be online in those two hrs before the official 10am UTC decks restart. 21 members played war since war started to first decks reset and played again after first deck reset at 20am UTC two hours after the start.
This screenshot is from the 30 minutes after war started. Mi clan and the Chinese clan had 10K fame already behind those who didn’t noticed this mistake. Supercell should make decks reset at the beginning of the race not location based or at a global time for all.
In my mini account clan the war started one hour after my main clan and had less time to do the same but also had time.