Installation error or something that is not obvious. It doesn’t make sense that you are at factory boost and failing when there is so many of us that are bore out, some others running high compression high boost turbo engines or very high boost application with OEM HG without issues. A little more info or profile filled up might help people help you. I remember that on my current engine I crosstorque the heads 3 times each in 3 steps torque each stud (ARP). It was a long procedure but worth the time. Installing the concave washers in the correct direction etc.