Oh no. I wonder what caused this damage to the dimples?

I'm sure this is a manufacturing defect. It's the 2nd to last dimple from the end and the the arc tube is quite solid held within the mica ends. Never seen this before though.

Yep, there's a hole to the outer bulb, the adjacent sodium mirror proves it. Pity, because these lamps are so rare now.

Would this have happened before 1st start-up or after? Cause it looks like the arc-tube blew out at the dimple.