Google scholar citation counting suddenly drops, very recently

Very recently, I had noticed that almost all scholars, from all countries and from all different universities, that I am aware of, their Google scholar citations counting suddenly drop (of the scale of 10, to 100 to 1000 to 10^4 counting, depending on your academic ranks and total citations).

One can check https://scholar.google.com/

Many people (almost all people) are affected.

Is there some policy changing?

Also it looks that the Google Scholar citation counts much less than ADSABS-Harvard system http://adsabs.harvard.edu/abstract_service.html, is there a reason behind it?