How much is a proper hole a broken ankle or a broken leg
If your fat ass steps and breaks through a sheet of metal and a strip of wood furring, you have no right even being on that or any roof!!
The furring strip is not the issue. depending on the climate, and the temperature differential along with humidity , the metal sheet will sweet on the underside and condensation will drip off the back. the warm air from the house will create more condensation on the back of the metal and not just in the little area. I hope the contractor has a membrane under the metal to stop water(condensation) from soaking into the sheathing and causing mold, or adequate ventilation opening at the peak to allow the moisture to be let out. As a Contractor for 30 plus years and a certified metal installer, these are my thoughts. Have a Great Day.
I don’t see a problem, however what was the stack for and why was it removed?