On iOS if a user turns off Bluetooth using the Control Centre, then Bluetooth is not actually turned off.
So, when the app opens and it tries to connect to a G30 controller, it tries to use Bluetooth (this check is present to ensure the user is near a Bluetooth controller so it reconnects properly).
Since the Bluetooth is not actually turned off, the user is prompted to allow for Bluetooth connections.
If you actually want to turn off Bluetooth, you need to go into;
- iPhone settings
- Then turn off the Bluetooth switch there