WordPress shows plug-in update, but I can't see any update.

When I log-in to the WordPress dashboard, it shows there’s a new plug-in update. Most of the time it shows there’s a one or two new plug-in updates. When I click on the update link, it doesn’t show any update? Also Plug-in page doesn’t show any update.

Apart from that, sometime WP admin bar shows there’s a one plug-in update, but plug-in tab shows two plug-in updates. But actually there’s only a one plug-in update. (First screenshot).

Sometime Admin bar shows there’s a plug-in update, but plug-in tab doesn’t show new update notification (3rd screenshot).

I don’t have any pirate plug-in. All of them are downloaded from the WordPress dashboard. There’s only one premium plug-in, its WordFense premium. It’s also a genuine plug-in.

These screen shots are not any photoshop modifications. Anybody has a good idea what is the reason?

Screen shots:-

https://2.bp.blogspot.com/–5TZdC2pjo0/UZ7tOoWEO9I/AAAAAAAAKnQ/M5RSo9pFLxc/s1600/2013-05-24_0952.png

https://3.bp.blogspot.com/-EWdkDp4Rr64/UZ7tOvemS9I/AAAAAAAAKnM/yd4XFO9cln8/s1600/WP.png

https://3.bp.blogspot.com/-5Q581xcaDoQ/UZ7tNClUBdI/AAAAAAAAKnE/5DLre_8xE-I/s1600/wordpress.png