Hello all, so sorry I didn't catch this thread sooner, and I hope the Mods won't mind me chiming in to help resolve this, as I work for the parent company Fastco.
We only started received sporadic reports of this issue mid-winter and it took us a little time to isolate it.
It appears that at some point in 2017 Tesla changed the design of the front suspension knuckle on Model S and the new one has much less clearance between the upright section and the inner wheel lip.
The 19" version of our R187 has an 8.5" width, so 0.5" wider than the OE, but retains the identical +40 offset. This fit beautifully on all the earlier models, but the revised suspension upright is now so close than it can potentially touch the inside rim edge when reversing with the wheels cranked over near full lock.
As a result we changed the offset specification to +38 for all new production. This is low enough to ensure clearance on the 2017+ models while remaining high enough to avoid causing the tire rubbing issue on the plastic inner fender liners when turning that is sometimes experienced on the early year cars.
Note that if you do have this latter problem there is a revised liner available from Tesla that offers more clearance, and that can be a necessary fix for certain winter tires whose tread blocks will rub the liner even with the OE wheels.
So if anyone here is experiencing the front suspension rubbing issue with the R187 on a 2017-18 Model S, please contact your retailer and have them order the new revised offset version from us, which should be available next month. We will be glad to exchange them for you.
Please feel welcome to PM me if you have questions.