Issue with slider menu and smooth scroll

Issue with slider menu and smooth scroll

When "contact" is selected, the page scrolls down, but the slider only moves to "services"


- Only happens occasionally 

- Happens most frequently with IE9 and Firefox (of course) but happens with chrome as well.

- Contact tab is the only tab with the issue

Willing to offer design work in exchange for help (small logo, etc. see my website portfolio)

Thanks!