Its a bug?? Post Google Preview……

hi,
I am using latest WordPress & latest update if plugin.
but i found a bug in all versions of plugins!
I’m not sure its regarding to my site only , or plugin bug. 🙂
Here is the Description :
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I have a Android Games blog : http://www.Apkorigin.com
Well directly go to the point,
Whenever i publish a new post with title like ‘Candy Crush Saga v1.26.0 APK Mod [Unlimited Lives]‘
the text in “[]” are not visible in SEO preview! just like i used ‘[Unlimited Lives]‘, which is not visiable in SEO Preview , see the following image :
http://s25.postimg.org/fiskmeg7z/Wp_bug.png
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I don’t know its a bug or a plugin feature or problem in my site…..
Please replay. 🙂

https://wordpress.org/plugins/wordpress-seo/