Validator returns "Congratulations! No Error Found." for CSS with syntax errors in it

[kupietools]

The following CSS validates correctly:

b {text-decoration: underline solid black;}
/* .disabled-attribute{display: block;} */   %
!
)
/* .another > .disabled > .attribute {box-shadow: 10px 10px 20px RGBA(255,255,255,0);border: 1px solid hsla(0,0%,100%,.2) !important;} */

span.greentext {color: green;} 

Instead of reporting the error when it encounters the invalid characters, it simply stops validating and reports that the CSS is valid.

I've put together a working example of this at https://github.com/kupietools/W3C-CSS-validation-bug.