After dealing w/ many Chinese suppliers in various industries I believe the blame falls on the OEM. If you ask for cheap garbage then you'll get that. If you ask for tightly specified designs that are properly designed for the process at a reasonable price then you'll get that.
In this case it's BOE panels that is causing it. Even Apple has touted BOE as a supplier multiple time in the last 5 years, but they failed to meet Apple’s quality standard.