That looks like mould , do you know what your RH is sitting at? What’s your ventilation like and do you have any fans to circulate air in your grow space
rh 26% lots of air movement
Is it growing on there. Can it be wiped off at all
Did u give it a nutrient mix and pour it where that leafs around?
That RH is way outside of the productive range, and now I’m wonder if it has something to do with this. It looks necrotic.
Can you detail the entire grow environment by filling out a support ticket?