Hmm this is not rare. See the 4th move of white in this game also.
It seems it is just a display bug as players seemingly can't "hit" the blot and as one can see later in the game(6th move) when the white checker leaves that point the black checker is revealed again.
(sakla) If you click on a person's name and then click Finished games you will have a list of games that have been completed, then click on the name of the game to get a summary of all of these games, then click on the name of the game again and you will have a game to view and analyze. (Servant) (Bütün ipuçlarını göster)