I'm 99% sure that its due to ypu sprayng the leaves with water and the light burning them afterwards as they act like a magnifying glass.
If you spray like that, turn on the fan so it dries fast, otherwise just use your water in the soil, even if sprayed, aim at the soil, only spray the leaves if you are applying pesticides or delta 9 enchancers.
Good luck, hope it answered your question.
If you pick my answer you are helping towards my goal of getting a fastbuds tshirt, thanks.