So, it's usual for users to re-evaluate the apps? This never happened to me on Google Play.
I'm genuinely curious because this didn't happen until this week. I've had a steady growth of 5-star reviews and suddenly, this week, 9 5-star reviews are missing which is almost a quarter of what I had and I haven't even updated the app or changed a thing. I'm really concerned and want to do something about it!!! It's also annoying to see there's no way to track the reviews, no history to show increase or decrease, which is available for many other metrics, but not for this very important one.
Also, are Apple's rules for proper reviewing shown anywhere? It is already hard enough to get reviews so the least Apple could do is let users know if they're reviewing wrongly when they post their opinions.