Hi, which browser are you using? I’m not seeing this effect in Chrome or Firefox. Or maybe I don’t understand exactly what you mean…
I noticed an error occurring when I click that particular post: “Uncaught TypeError: Cannot read property ‘hide’ of undefined”. This might explain the unexpected behavior.
Sadly, I have no idea what causes the error. Your only option is to disable all other plugins and test again. And if the problem persists, switch to the default theme.
What I also noticed: your current home page, even without opening/viewing any of the posts, takes 37.1 MB to download and over a slow connection (like mobile 2/3G) it can take over 4 minutes… I’d advise changing all PNG images to JPG and then use maybe an optimisation plugin like Jetpack (Photon module) or WP Smushit to optimize them further. This should make the page load a lot faster.