HDR zooms in when enabled


I’m on PC, with a GTX 1070 on Intel i7, and I like to grab a controller and lay back in front of the big screen sometimes, so this -

I got a new TV with HDR, but whenever I enable HRD the screen zooms in about 300%, untill I turn it off again, sometimes it doesn’t zoom back out, and if I enable it again after this, it zooms in even further! What gives? Anything I missed here? Does it have something to do with running HDR in 1080p resolution? Any help is appreciated.