I read that article too. For what it's worth, C&D and Edmunds test have one thing in common, and that's Cargos Lago. Now FYI, I've been watching him for over 4 years now and really like the guy (he's an excellent journalist), but he is the only one I've seen say they Plaid is unstable at those speeds. Perhaps I've missed some, but people like Tesla Plaid Channel who repeatedly take the car to 150+mph have never complained about it.
Now regarding how Tesla could address this, I think it would be quite simple, depending on the direct cause. As
@lolachampcar has IIRC highlighted in the past, sometimes the yoke combined with the harsh acceleration will result in driver induced oscillations, causing the car to feel more unstable than it actually is. I think the main problem Carlos had with the car isn't exactly the wandering itself, but rather the steering feel, which compounded any wandering that may have been caused by the yoke. So it's likely that Tesla could send out an OTA update, and just firm the steering up more, and that would fix it. At the very least, I think it's what Tesla should try first before making any major changes.