For example, when visiting the app at the link below called "Secret Chat (Random Chat)" on my Android device, I can neither see any general star rating, nor any reviews at all - it say "No reviews yet".
When looking at the app through a web browser I can see a lot of poor reviews, but still no star rating.
What's going on here?
The app in question, but there seem to be many like it: https://play.google.com/store/apps/details?id=kr.jungrammer.secretchat
As I remember, Play Store is only showing reviews in your local language, so maybe you don't see them because there simply is no review in your language?