At first I didn't pay attention to the flex issue, as my bike and many others here were fine, so I was thinking just about few defective ones.
After reading the great JJJ case study I also realize that the design is flawed and all frames potentially will show the flex issue.
JJJ fix is brilliant, Haideli one much less even if they invested in a new mold for rear triangle, obtaining the same result as JJJ on the upper link and maybe making it even worse on the lower; the triangle is beefier but this isn't necessary a good thing.
For sure the problem has to be solved on all frames, even the non flexing ones like mine: as haideli says carbon fiber is an anisotropic material (the paper sheet explanation); unexpected stress in unexpected direction can cause failure even with relatively low force; I would consider the frame dangerous without locking somehow the bearings in the recess.
The big question is if the old triangle section is strong enough after the bearings will be locked in place.
I am still positive that the fix will work and the bike will be a great bike as it is for now; for sure I don't want to invest 300$ in the new triangle or even worse 1000$ in the new haideli model.
We have to accept that we are beta testers of this frame, it's part of the fun too; just I hope at the end I will have a safe and reliable bike.
I am sure everybody isn't riding much due to winter season, but with the coming spring let's keep the community updated about possible failures or defects that this frame could bring.
Merry X-mas to all 831 team!