This past Sunday we reported that Google appeared to remove some query data from the query filtered search analytics or performance report within Google Search Console. Google today issued a clarification, explaining that it never showed these queries in Search Console but previously did include the hidden queries in the overall sums in the charts. Now Google is also excluding these anonymous queries from the sum.
Google wrote on Twitter:
Of course, seeing huge drops in the sum of your query data when the query filter is added can make things look bad. But you need to understand that this is not an indication that your site is performing worse in Google but rather that Google has changed how these reports calculate — thus what may appear to be a dip may be nothing at all.