CSS Validator Bug: "applies to top-level elements" warning

Hi,

There seems to be a bug/erratic behaviour in the CSS validator.
If you repeatedly validate the following snippet of CSS, around 50% of the
time it will validate fine...
The other 50% of the time, it will come up with one or both of the following
warnings:

This property applies to block-level elements. : div.header

This property applies to block-level elements. : p.header

This happens when validating using either of the File Upload and Direct
Input methods; I have not had the opportunity to check validation by URI.
This behaviour is reproducible, although you may have to validate the
snippet several times in succession before getting these warnings. On the
other hand, you may get the warnings the first time you validate the
snippet!

Tim Boalch.


========================================

body { font-family: sans-serif;
       font-size: 10pt;
       background-image: url(background.png);
       background-color: #FFFFFF;
       color: #404040;
       padding: 24px;
     }

a:link    { background-color: inherit; color: #0000FF; }
a:visited { background-color: inherit; color: #6A2D88; }
a:hover   { background-color: inherit; color: #0000FF; }
a:active  { background-color: inherit; color: #00A000; }


div.header { margin: auto;
             text-align: center;
           }

p.header { background-color: inherit;
           color: #808080;
           font-size: 36pt;
           margin-top: 12px;
           margin-bottom: 24px;
         }