When I search for keywords on istock, the results sorted by Best Match are now completely different and in my opinion are not top quality images. Has anyone else noticed the change? I hope it's a temporary glitch. If not, many of my best sellers will be buried in favor of (again in my opinion) inferior and less relevant photos.

It seems to be fine unless you filter to "All Content" in which case the results go haywire. Filtering to a subcategory such as Images, Photos or Vectors returns the expected results.

iStock has always had a rubbish tech department.  Probably transferred to Getty these days. who are equally as bad.