Earlier this year Google announced that in November 2021 they would be adding a country breakdown to ratings as Google ratings were always reported under one, global rating.
From what we have observed over the last couple of days, Google has begun to slowly roll out the changes for some apps. Based on these changes, some developers may see an unusual shift to their ratings starting November 18th and on.
One important note is that these changes are currently impacting the star counts, only. As it stands, the total star count remains the same across countries.
We'll continue to monitor any and all changes from Google's ratings and provide updates as they are detected.