Leaves looking weird

Looks like possibly some powdery white mildew, looks like the chlorophyll degraded and replaced with Anthocyanins which cause the purple hues, any chance they had a cold snap? Adequate ventilation under canopy? Id also hazard a guess at mild over feeding of synthetic fertilizer, salts that are taken by roots as they uptake the water, salts have no way back down once water makes its way to the leaves getting trapped in the leaves the circulatory system, purchase some NPK RAW ENZYMES and NPK Humic Acid and apply to every watering until symptoms dissipate, the enzymes will neutralize the salts build up in the soil and the humic will help with the flow of nutrients and provide a method the plant can use to dispose of unwanted salt uptakes in leaves. Improve aeration and make sure night temps are not dropping below 67 where chlorophyll degrades.

Hard to say without smearing the plant bro but I would just get rid of it if it’s the only leaf. Post another question with pic of plant and where leaf is and other leafs!!!