There seems to be a Google update happening again. This one is not announced by Google and webmasters are relating it to the Bert update.
I personally have not seen any major changes on my field sites but many people are complaining about crappy websites ranking high.
Below are some screenshots taken from popular webmaster forums:
There is no clear information as yet if certain types of websites were affected. Do you see any changes to your websites?
Discussions on:
https://www.webmasterworld.com/google/4971024.htm
https://www.blackhatworld.com/seo/is-there-any-recent-google-algorithum-update.1176382/
https://www.blackhatworld.com/seo/are-you-noticing-google-algorithm-update.1176344
Google does make algorithm changes and chances are that your website might gain or lose rankings.
If you have lost rankings and traffic, I would recommend not to panic and wait for few more days. A lot of such updates take days to roll out. And there are corrections made in few weeks as well.
Hence, just keep looking at your stats for a few weeks and do not make changes assuming that Google does not like your website anymore.