iPhone infra red light (front and back) is flashing constantly, caught on night vision camera.

I have noticed when my wife is with our baby with her iPhone, on the night vision camera her phone is constantly flashing, both front and back of the phone.

I first asked if she could see it flashing, which she can’t. I then thought perhaps it’s faceID, but it’s repeatedly flashing, perhaps every 5-10 secs. Also if it was faceID why is the back light also flashing. She sees the same with my phone when I’m on the camera.

There must be some technical explanation, but it feels kinda creepy that maybe the camera is operational and trying to be covert.

Any ideas anyone?