It has the Alternaria leaf spot look that I have seen a lot on ornamental plants over the years. Warm and moist conditions are factors. Seen it even cooler but free moisture on the leaf makes it worse for me. Probably the same on tobacco. Thats my guess.
How's the color curing going on that first big batch of leaves you hung? Should be yellowed and starting to wilt and dry huh? My last set of dark air black mammoth and burley is yellowing and starting to finally brown after 6 days.
Ive got 2 sets of primings hung and yellowed since then in my color sure chamber but my conditions are more controlled.
25 C. And 70 to 79% humidity.
When I get mold, I just cut that 4 or 5 cm piece of stalk and a bit of lamina with scissors and throw it away. If I get the house burn rot I throw the leaf away if I didnt catch it in time. I find by keeping it warmer and more humid shortens the time of risk for me and I don't worry much about green leaf.
The last sets of primings are slower to cure for me. I think the cooler nights have slowed the.leaf ripening.
You have a lot of leaf to show for all your hard work. Now perhaps you wont have to drive so much.
Great Job!!