Let me illustrate:
http://www.chesscube.com/play/app/?open ... =253120721
In the game, what actually happened was, after I castled (18. ... O-O) and his immediate move (19. Bd4), my rook disappeared and my king moved (by itself) to h8 instead of g8! This also explains the "glancealot CHECKMATED" at the end, when i am NOT checkmated according to the PGN file when you replay the game, see picture below
This would repeatedly happen when i play against this guy, my pieces always go missing after I castle. It has not happened against any other player.
here are two more examples against this guy, i resigned in both games because my pieces went missing!
http://www.chesscube.com/play/app/?open ... =253396092
http://www.chesscube.com/play/app/?open ... =253396573