I use version 2.0.23 of the Post Grid plugin and the thumbgoleft effect. But on iOS devices it is not working. The image will not be hidden.
After I have added 'onclick="void(0)"' to the div statement (class-shortcodes.php, line 102) it is working on iOS devices.
Welcome to our forum, this is probably CSS3 issue, although i just update plugin, can you please update plugin in version 2.0.24,
please make sure you clear browser cache and css file loaded the latest files.
Let me know the result.