Why is it still running power after I have turned Android app to the background?

Hi, the new version of Android app has adapted to the Android 8.0 system. The new rule of Google is that if an app needs to establish a connection with the server after it has quit to the back-end, the app is obliged to make a notification to inform the user that it is running in the back-end, so there comes this notification. It is not displayed because the system decides that the Tuya app consumes so much power, please rest assured.