English checkers rules

I'm very sorry, but according to the rules of English checkers, if a piece reaches the last row during a move, it cannot be moved from there immediately, but can only be done on the next move. So I would like to ask you to correct the mistake.

Can you point to a specific game where the error occurred?

http://www.vint.ee/index.php?page=32&game_id=67028&game_type=1

Yes. This mistake was probably due to ignorance - I just didn't know the rules of English checkers well enough :) - But thanks for reporting it - we will fix this mistake soon.