Sad thing about the validity of this claim is that there's no verifying the actual source of malfunction.
We can't necessarily blame the bike company, when it could have been a botched assembly, or it could have been a tampering with the assembly later.
Not disagreeing with you. But it is common for parts to break a lot on modern bikes. Bikes are not made like they were decades ago.
This is an entirely baseless claim.
Fabricated events or evidence can easily distort the apparent truth.
However, legendarily, poor assembly has been a known cause of malfunctions like this.
There is more than on person on the internet saying, carbon fiber bikes are not made as precisely as metal bikes, and problems with bottom bracket do occur.
This kind of thing on the internet, might get the attention of bike manufacturers, and they may put more attention into making frames more precise.
Someone may also come up with a different system for installing the bottom bracket.