I always thought the bubble in the tears are from the laquer that has released from the surface. But after comparing it to some other original screen used helmets it was always there. Another reason for that could be that air was catched in the tear area. If the vac machine had a standard configuration of all settings like vac pressure, heat and position of the face mold the bubble could appear always there. It can appear nearly always the same shape. So it looks like it was part of the mold. That was just a thought. The different pulls in sharpness speaks against this theory.
Marcus