HTML includes a quote element, <q>, for displaying localized and stylized quotation marks. When this element is nested, the rendering of the marks changes from double-quotes to single-quotes (by default). The spec on this is here:
And an example can be found on section 2 of this page:
Note that WebKit incorrectly renders the inner marks as double-quotes. Confirmed on the r15924 build.
Bug 3234 states that the inner quotes are rendered as single hash marks (apostrophes) - that's not what I'm seeing. Anyway, that bug is basically about the same issue.
*** This bug has been marked as a duplicate of 3234 ***