It must be to do with bumper shape or just plain cost cutting.
Because of the low numbers made VW won't have bothered engineering in anything that would have cost them much.
The specs on the cars are odd.
Ambient with leather but not with normal cloth seats.
No winter pack with normal cloth seats.
Hit and miss whether you get red edged belts...
And so it goes on.
The only ones I've seen photos of with front bumper sensors were retro-fitted. Apparently an easy job and a good idea if it's a daily driver. There are lots of things sticking out of the front bumper that are easily damaged if you're a bit tight on space. I tend to try and leave about a six foot gap when manoeuvring!