Macchia chiara/scura su di una foglia

hey 👋 unlikely, but still, check for small pests like leafhoppers or aphids, especially under the leaf. Give it a little shake ; if nothing moves, no worries 😉

Tanspirational bulk flow (mass flow) is susceptible to inadvertently "sucking up" sodium (Na+) ions. Kinda like when your just gobbling down food and a tiny piece goes down the wrong hole. Would never worry about a single isolated blip.

looks like a bit of damage. Maye some water got on a baby lead and burned it a bit when it was growing out. or something damaged it from moving around, does not look pest related. I would not worry about it.

could be Ca def