It's very odd. I am super-admin on one of our Joomla sites, and daily go through the forums, liking and thanking posts as required. 

FREQUENTLY, I will like a post, and then I can't THANK it. Nothing happens when I click the thank button.

Lots of posts I can  thank, or like and thank. I can always like (or dislike) posts. But quite frequently I click on Thank button and nothing happens! I have tried loggin out and in again, clearing browser cache and cookies, and clearing the Joomla caches. NO CHANGE.  Very strange!! What could be causing this?  (I have not tested extensively, but have never noticed this problem with any of my standard user test accounts, just this admin account)