I think the car antenna/sensor is somewhere near the area I circled on the photo. I just reroute the rear cam cable down to the floor avoiding that area, the proximity key works much better now but still not the same as without the rear cam connected.
The longer cable is just enough for such a smaller car.
Can you check this for a 2016 Subaru Forester 2.5i Premium without push-to-start (normal key fob) routed along driver's side headliner? I had this same issue in the past with the SG9663 DC Pro (confirmed by dealership techs by testing with dashcam unplugged and plugged) and I learned to live with reduced range. Since the SG9663DR come with ferrite cores I was thinking it might be worth a shot. @Street Guardian USA