Oh, I think you're referring to the "Computer Modern Serif Slanted" sample (not the "Computer Modern Classical Serif Italic"), right? Yes, the @font-face rules

Oh, I think you're referring to the "Computer Modern Serif Slanted" sample (not the "Computer Modern Classical Serif Italic"), right? Yes, the @font-face rules for that family have 'font-style: normal', whereas they should really have 'font-style: oblique' which would have avoided that ugliness.