Facetime not pausing when on another app

Is anyone else having the problem of the person on the other end of your FaceTime call being able to see you while multitasking? Nearly every time I get on FaceTime with a friend lately, they say something that would suggest they can see me while I’m on another app, and soon confirm that they can. It’s very uncomfortable, as I don’t know when my camera is truly on and off. They also have a new iPhone, so I’m assuming it has something to do with the update, as they hadn’t done the update prior to getting the phone. I have not updated my phone to iOS 13.5.1 yet.