I saw another post about it, but the person posting was not explaining it correctly. Here it goes, after you win a level and earn stars, go to the dice game “Roll around the world”, after rolling one or more dices, when you go back to the main screen, your recently earned stars will vanish. You will need to swipe up on the iPhone as if you are going to switch to another app, and when you are back in the game, your stars will be replenished. This is an annoying bug that has been there for months!
Developers should act. We are watching ads, generating you revenue, therefore we are paying for this service.
For reference, I also have the latest version 1.18.82 for iOS.