Such apps will never give you correct signals so avoid trading by following such apps. An ordinary web developer can easily create such apps so it is better not to trust all apps so easily. If you search the Play Store, you will find many apps that claim to provide 100% accurate trading signals. They make such claims only to increase the number of users of their app but if you believe them and install their app and trade according to their instructions then you will definitely get hurt. Rely as much as you need to on your own trading skills, there is no need to follow other people's trading strategies.
Buddy I think you get the indicator apps on a wrong way, Because indicator apps doesn't gives any signal and that is why there is also no chance there they will give wrong signal. Indicator apps help with the different kinds of indicators for technical analysis, what will make you define or make a signal for the multiple cryptocurrencies. And proper Indicators are the thing that can make or gain your trading skill so it is always has a value for doing trading.