Duolingo works incorrectly with Moscow time zone.
My practice time expires at 23:00 not 00:00. Please, correct the issue. We do not use daylight time saving since last October.
While mobile version shows time and XPs gained correctly, your server accounts all XPs gained between 23 and 00 hours as points for the next day.
Your time zone if fixed to the one you were in when you first registered. If that was during a daylight saving period you will always be 1 hour out when you revert back to normal time. You will just have to adjust you learning habits.
The thing is we won't go back one hour. It will stay the same. That is the issue that needs to be corrected.
I don't think Duo will change it, but you could try via the support button. If they can't then you will just have to get used your Duo day being from 11pm to 11 pm the following day. Other than that, it should not be a major problem