Reviews and ratings disappearing

Starting this week I had 41 ratings and 6 reviews. The number has been diminishing during these few days, when I woke up this morning I took a screenshot of the current amount of both and now the number is even lower. I've read other threads exposing the same problem but couldn't find a solution. Why is this happening and what can I do to prevent this?

Same is happening with my app...

I also observe that the number of ratings come and go. Rating number increase and decreases again.

My guess was that ratings are deleted when a user uninstalls the app, but this is not the case, right? Why do 5-star ratings continuously disappear?

I find it unfair that bad ratings, that are several years old, have the same weight as if they were given yesterday. Google Play has a different system: The app rating is not the overall rating but is based on a period of the last months (not clearly specified). This is much more fair and informative as it respects the current and not the initial quality of the app!

Reviews and ratings disappearing
 
 
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