After you have analyzed the problem together with the team, and there is evidence that working within the AET has no problem. Probably caused by PCB mix comes from Chinese vendors because it brought the AET.
After the problems with the team. And there is evidence that it works within AET no problem is likely due to PCB mix from a Chinese supplier. Since the AET is imported.
After analyzed the problems with the team. And there is evidence that the work in AET problem seems to be caused by PCB mix distributor from China due to a AET imported.