Almost regardless, at this point in the production process vehicles are subjected to rigorous testing precisely to find defects in design, parts specifications, supplier performance and myriad other factors. They also test to establish precise and dependable performance, actual crash performance characteristics, severe weather, harsh road condition capabilities and on and on.
After decades of experience with such testing I have never heard of nor seen any case in which testing did not yield changes in design, component specifications and production processes.
So, whatever this could be, it is most unlikely to be anything consequential from a production perspective. Unlikely but not impossible.
There are at least a half dozen people on this board who've worked on such programs. Although I have decades of participation in such programs I am not an engineer nor industrial process control expert. Thus, others know more than do I. To my knowledge alternative suppliers of major parts can frequently be found in extremely short times, much shorter than normally imagined. Of course that costs, and produces air freighting heavy items normally shipped at sea. There are always solutions unless the basic design is defective. For the Model 3 that would have long ago been evident.