App performing continuous background activity - even during terminated state

Question

I just noticed that my app's background activity is sky-rocketing after few mins of usage.

1. Location permission disabled.
2. App's background refresh disabled from the iOS Settings app.
3. Push notifications enabled.

It keeps on getting launched/running in the background, even after I have terminated the app from the Recently Used Apps window by swiping up.

Any leads on how to debug is very much appreciated.

I have shared the battery usage %. Also, Xcode's Battery Usage stats from the Organizer-tool

Battery Usage stats per version

Battery usage %

Observations:

1. Background activity stops when the phone is restarted.
2. Background activity happens even when I have disabled Background App Refresh or in LowPowerMode