Specificity and conflicting selectors

Hi,
I have a question about how to handle selectors that have conflicting meaning.
The background for this question is a webkit bug https://bugs.webkit.org/show_bug.cgi?id=52511 .
In that bug, the "right" selector has a higher specificity than the "left" selector, yet all major browsers ignore the "right" selector and display the image on the left side.

Should browsers be expected to have the knowledge about these conflicting selectors?
thanks, Yael