1 curling leaf

Nitrogen toxicity, this is one of very first signs good looking out 💨🔥

Dovrebbe essere un over Fert! Dai acqua per 2 volte e riprendi a fertilizzare con più parsimonia, hai una penna tds-ppm?

Are you trying to grow leaves or buds my friend? See how dark green and almost shiny your leaves are?? Thats a bad sign in flower, means too much nitrogen and prob also a touch too much magnesium is also likely, so are you running flower nutes or veg nutes?? Id make your nutes weaker in strength and rip off that leaf to be on the safe side. And double check your using flowering nutes not veg nutes ok? Remember we are trying to grow flowers here not leaves, at this point as long as the leaves stay attached to the plant-they are fine, you can ignore them. Worry how the buds look-thats what you want to harvest right?

Waaaaaaay overfed and bordering on nitrogen toxicity.

Could be your soils a little high in nitrogen. I'd water with just ph'd water a couple times. It won't fix that leaf but should stop it from spreading throughout the plant. All in all great looking plant.

Look like nitrogen excess.