Slider problem with Joomla 2.5

I have an small problem. I using the slider in a joomla 2.5 CMS.

The slider is in the header from the site. The slider works on the main-site and
the main links, but he dont working under the sites in the navigation from the

work on: → Main test site
work on: → Main link site
dont work: → Submenu link site

anyone have an idea…some known joomla bugs??? THX.

If i turn off the seo friendly url-modus its work. why???