Sticky header issue

I have one issue with sticky header JS / CSS and Litespeed plugin. If I set the option to “Load CSS Asynchronously”, the sticky header have problem to calculate the right height of the header, respectively the content under that. Sometime is calculated right, sometime it shift the content below (around 400 px down) and leave white space in between. Any ideas how to exclude this header css from the main css to exclude it from loading async..?

The page I need help with: [log in to see the link]