Not strange at all. Even the most correct player in the world might get a red card once. Game engine generates a foul, a certain randomness is added to judge it penalty or free kick, a certain randomness is added to judge it normal, yellow or red card. It's like throwing a dice in the end. I lost count on how many times i got a yellow card, subbed the guy and in the lapse between the sub and the click he got expelled, live with it. :P