Another Google Scholar Purge

Google Scholar has again gone through a process of forgetting or purging a number of citations to my papers.  This time last week it said I had 1,589 citations to my work.  Today, 1,170 (both figures down from 2,130 in January last year).  Google Scholar is fairly opaque in how it does things, and I don't know what records it deleted and why, but it seems unfortunately very unreliable.   As a record of my papers, it's useful.  For citations?  It's becoming increasingly less so.  Anyone else noticed the same with them?

After noticing (some years ago) strangely fluctuating numbers coming from Google Scholar I started periodically recording the number of citations it reported for me on a spreadsheet.  Hence I can present the graph attached here.  The latest downward line is smaller than the one I noticed mid-way through last year, but still takes the number of citations back to that of around 5 years ago!