Content is missing in both a nightly and in 10.4.7. Content is rendered as expected in firefox.
Created attachment 10012 [details] Reduction The original page contains two unclosed "object" tags. The second one has no parameters, so I assume it is intended to be the closing tag of the first and has simply had the / omitted. This reduced test case demonstrates how we handle an unclosed "object" tag differently than Firefox, leading to content not being displayed.
*** Bug 12708 has been marked as a duplicate of this bug. ***
Today WebKit does display the content in the reduction with a vertical border line after it, Firefox and Opera display a border line before and after the line of content.
OK, although we display the reduction slightly differently from other browsers (and they differ among themselves too) - the original bug has been resolved, WebKit does now display content after an unclosed object tag. I don't think there's any right or wrong way to display an unclosed object tag itself so I'm going to close this bug. Please re-open if there's something to do here.