Its only the first frames that have the flex issue , The new frames with the upgraded rear triangle are great
I only have one ride on the upgraded triangle and it is already night and day a better riding bike. Super supple similar to the double bearing JJJ bolt mod, it is a similar design, and actually has the proper amount lateral stiffness.
The original triangle was my only complaint and I'm hoping that it is solved now - need a few more rides to be sure but I am impressed so far.