If your Android app has paired with your device before, and you update the Gatt structure of your BLE Slave / Peripheral, you will need to clear the cache Android side, else the Android app will continue to show the old Gatt structure.

To clear the cache, all you need to do is toggle Bluetooth on and off. With this done, the cache should be clear and your new Gatt structure will be picked up when you scan and connect to your device again.