BUG in 2.1 – character n with a hook (ň – ň)

I got problem with version 2.1 – character ň (n with a hook above, used in czech language) is retyped to some stupid two chars (??). All other chars (include some other czech-specific) are ok, so it is not a char coding problem (i use utf-8). All webs I did with older versions were OK.