Update from Google!!
Google Search Analytics Report Updated To Better Account For Lower Position Results
Like many other webmasters have you also experienced a decline in your average position metrics? If so, do not worry, there’s nothing wrong from your end. This is because; on 19th July 2017, Gary Illyes from Google has confirmed a feature change in the Google Search Console Search Analytics report.
— Gary “鯨理” Illyes (@methode) July 19, 2017
As per his tweet, Google has amended the data anomalies page to convey the change of an “incremental improvement in Google’s logging system now provides better accounting for results in lower positions.”
The good news is with any of these reporting changes; it will have zero impact on your real search rankings.