This isn't a manufacturer defect, it's a harsh reality that can befall any particularly heavy GPU that is not vertically mounted and has no GPU support bracket installed as well.
As someone who does warranty / refurbish / RMA related repairs for a number of large electronics and PC component manufacturers I've seen this over and over again first hand with larger GPUs across every single manufacturer including NVIDIA's Foxconn manufactured FE models. The number one cause of this type of crack near the PCIe slot retention bracket is a combination of the sheer weight of the cards, gravity, time, and no decent GPU support bracket being installed on top of it all.
At best, you don't wind up with a cracked PCB and instead the flexing of the PCB over time leads to solder joints under the VRAM or GPU Core breaking which will result in either artifacts / no video / no fan spin / etc. This is exacerbated when an individual or a prebuilt manufacturer ships the PC or moves the whole PC with said card installed in the system still.
Gigabyte is slightly more susceptible to this causing damage that leads to the card no longer functioning as intended for the simple fact that they manufacture their PCBs with several critical data and voltage traces running much closer to the retention hook then other manufacturers but it has nothing to do with PCB quality or defects.
This is the same reason no manufacturer will accept warranty repairs for this kind of damage because it's technically the fault of the user or the company that purchased the GPU to be installed into the prebuilt system.
Do I believe manufacturers should be more transparent about how critical a solid GPU support bracket is to the longevity of these larger GPUs? Yes. However, the damage that occurs from these combination of factors ultimately isn't the fault of the manufacturer.
Also, there is a typo in the heading. It's NorthRIDGE not Bridge.