website naviigation oddness on an iPad

If you look at my website http://gholman.magix.net on an iPad and tap one of the blue icon images it will jump to the relevant section further down BUT the sticky menu at the top ceases to be responsive unless you swipe the screen up or down.

Does anyone have any idea why this is happening and how to fix it?

I can only confirm that for now but I've no idea why it's happening :(

Hi Egg, thanks for confirming you see it too.