Hello fellows, I grow under LED light, all elements are good including the PH, in one of my autoflowers there's many leaves like you see in the picture, I don't think it's mites or thrips problem, it's growing inside a sealed growtent, indoors, n whatever it is it never comes off, I try rubbing them, but they're still there, so it's not powdery substance you get from mites, n it all appeared overnight, can anyone identify the issue plz?