We are facing similar issue on our application. Our application get killed on background on iOS15.2.1 and iOS15.3. It seems to be no problem on iOS15, 15.1. I guess high cpu usage rate threshold has been lowered from iOS15.2.x. (maybe from 80% in 60sec to 15% in 60sec!!). I hope this change will be reverted on future iOS release or I would like to know workaround this problem.

this is mistake. please ignore this answer.

To Sam_V and Svantulden, Are your app using CoreLocation in background? In my case, the issue seems to be gone when I stop using background location even if cpu usage rate exceed 15%. But our app definitely need background location...

I have tested on iOS15.4 beta4. I’m not 100% sure but the issue seems to be gone.