Can't say how widespread this issue is, but on my Feb 2015 build, it had become such a major issue for me that my satisfaction with the car was diminishing quickly. I had it into service twice (including Fremont) to correct this problem and despite adding various bits of felt tape and thick foam pads to several parts around the inside of the dashboard, it persisted. I finally decided to take matters into my own hands, methodically taking apart the dashboard around the glove box assembly myself. Fortunately, everything was extremely easy to do with nothing but a Torx T20 driver in hand. Assuming the rattle was originating from the passenger vent assembly I took it completely apart and put it back together with some thick packing-style (Gorilla-brand) tape between static parts to isolate them. I also put some felt tape between the vent and the carbon fiber trim. I even put some felt tape in the thumb slider part of the vent to ensure smooth rattle-free operation. However, none of this really got to the core squeak. I finally discovered that what was causing the squeak in my case was that the passenger-side foam vent duct was rubbing against the horizontal structural frame member (a ~3" diameter steel pole) that spans the car inside the dash. I simply placed a few pieces of PTFE tape (you could probably use felt or something similar) at the point on the pole where it contacted the duct and voila, squeak completely gone. I put the passenger dash back together in minutes and it's been completely silent for several days now. Here's the passenger side dashboard with glove box and trim pieces removed. Really easy to do with a Torx T20. 7 screws and a bunch of clips and you're all set. The culprit area with some PTFE tape applied to the steel pole where it touches the foam air duct.