Benzelsanswered grow question 3 years ago Not sure what causes it, but have seen it before- cut the affected parts out NOW!! It will have mold in it very soon if you dont and it will spread fast if you dont cut it out. The damaged parts are dead anyways and will just infect the other parts of the plant if left- it wont recover no matter what you do.
It could be light burn but it is also hotter higher up so could be temp burn too from the light heat. Either way its gone so get it out before it causes more issues ok. The rest looks good so be glad you still got that.