Just came back from St Maarten to Madrid Barajas, a 7 hour flight in the A310 (very favourable winds).
It was a night flight. Something happened at midnight, and the sim aparently changed from 00h to 12pm.
I was doing some home maintenance during the flight (a good way to keep my wife happy with my sim hobby, since long haul flights for her mean “house-keeping-stuff-being-done-in-the-meantime”), and when I came back to check for fuel burn, the night had turned into a bright midday.
Had to manually change the hour back to 00:something, and continue flying. No problem, anyway. All 7 hours were logged correctly. I had never seen that, and I cross the pond frequently.