valve randomly added a command to break demo playback by making it work like cs go. As a result demos are recorded at 16 tick rate b/c that is the obvious tick rate a cs:go player would want to have things recorded at. This setting was then applied to cs:s with no documentation or notice.

I have made it 66 on cs:s and 128 on go so that it will be the exact same as the server tick rates.