Looked at your photos of your Inspection, and have a few un-answered questions of my own. This is unusual.
The cracked plywood to me looks like it was hit and broke the bottom layer, possibly due to a thin layered plywood and bundles of roofing dropped to hard when done initially, or when the metal was done.
I see that there are no H-clips visible in two of the photos and the dark stained underside of the sheathing was definitely cause by heat loss during the Winter months and continuous frosting and thawing over the years. I have seen this before up here in my area.
The insulation appears to be of only an R-19 and storage in the attic might have negated it’s insulating qualities.
No proper vents were installed and one picture is showing the insulation stuck to the underside of the roof sheathing which is another indicator of frost on the underside of the sheathing during the Winter months.
I am also surprised to see a dwelling of this size approx. 28’ wide with a 6/12 pitch roof with 2"x8" trussed rafters.
A House this size with 2"x8" trussed rafter would only tell me this is a full walk-in attic from somewhere, possibly walk up stairs or fold down stairs where more heat loss is occurring. The furniture at the gable end would indicate that the attic was used for storage. The 6/12 pitch roof would have given them approx. 7’ 0" of head room.
Walk through attic truss design have increased rafter sizes due to the configuration.
Was there bathroom vents and dryer vents discharging in the attic?
One more puzzle, if the roofing shingles were left under the metal roof, why do we not see the nailing pattern penetrating the plywood.???
Hope this helps in solving your problem or I made it worse. ha. ha.