Not sure if anyone else has experienced this, but having put a sticky menu at the top of the page, the anchor link (by default "services" in Fixer), takes the visitor to the next section of the homepage, but the top of this section is hidden by the menu. So the headers are invisible.
I tried a workaround by placing a blank textbox with an anchor above the fold (on the main homepage area) but this works! So it links to the area at the bottom of the main page and not the beginning of the next section. So I deleted it.
Just go to http://188.8.131.52/~optigenia and click on the arrow and you'll see what I mean. Scroll up and you'll see the missing headers...