There is no bug in the rules. Czech Checkers is just a variant played in our country and the rules details had been consulted with top Czech Checkers players.
From Checkers rules:
"If the player has more possibilities to capture opponent's pieces, he/she can select any of them. However, when a king or queen (in variants) can make a jump, the player cannot select a pawn to jump with."
(esconder) Se pretende jogar um jogo contra um adversário com capacidades semelhantes, pode definir uma gama para o BKR do adversário, quando cria um novo convite de jogo. Dessa forma ninguém com um BKR fora dessa gama poderá ver/aceitar o convite. (Katechka) (mostrar todas as dicas)