Open the link http://docbuilder.usersys.redhat.com/13968/#About_This_Guide in Firefox (tested on Firefox 17 and 24), and the first time the browser will not stay at the top of the page. The second time the link is entered, the browser will scroll down to the correct position. Chrome works OK.
This seems to happen with all anchors in DocBuilder pages.
Building the book with Publican and jumping to anchors works OK.
I feel silly because I've noticed this for quite some time but thought "It must just be me"
Including jquery (even without any other scripts) causes this.
I'm not exactly sure what is causing this, but moving the jQuery script to the end of the HTML page instead of in the head fixes the issue. There is no real downside to having the page load before the scripts (and all the scripts run after the DOM is ready anyway). Any newly built specs will have the change enabled, and all books will pick it up with the next full rebuild.