I’m not seeing any problem with this page on iPad or iPhone. The header scrolls down to the spot at the top of the viewport, just as intended. And it scrolls back up when you move the viewport back up to the top of the page. I do see that the header bar is not making it all the way across the screen, but that’s not something that Sticker has anything to do with. All it does is fiddle the top offset of the element it’s applied to.
However having said that it is possibly linked to a page with embedded code, i have still had the banner “Stick” in the middle of the page if there is no embedded code, but it seems to be more common if there is.
This issue still persists, not only on my ipad but with iPad users of this site.
I have noted that on the following page is you scroll down on the ipad the header “follows” you down, and then if you scroll back up again it sticks but also i note that part (excluding CSS Navigation bar) of the Banner still exists at the top of the page.
I have a iPad 2 with latest iOS. Understand your issue. Have it here too.
Don’t know a solution, but if you want de headerbar always being visible, you can also choose to position it on its fixed position at the top of the page, letting the contents of the page slide under it.
I did this on my page: http://www.appadvies.nl it is in Dutch, but you can see there how it works. I thought this could maybe work for your site?
I tried you solution, but it causes another issue for my site, in that the Header banner now always displays to the left of the browser screen and not in the centre. I think this is of the way i originally set up the page.