Trigger housing alignment issue

I bought a steel trigger housing for my PTR. Without the trigger pack in, it aligns & sets just fine. But once I pop the trigger pack in, it gets stuck. Any idea what/where the culprit might be?

I bought a steel trigger housing for my PTR. Without the trigger pack in, it aligns & sets just fine. But once I pop the trigger pack in, it gets stuck. Any idea what/where the culprit might be?