Bug in Counter-Strike 1.6 (Counter-Strike)

Yesterday, as usual, played on the platform FastCup.net I go into the game and see that in place of the sight I have a small, static plus. It was not familiar but soon became very comfortable, especially on long distances. The sight is not expanded when fired, did not change when changing weapons.
Looking for info all day, nothing. Somebody met with such?
I really want to repeat this bug and play with that in mind.