MPK Auto & 2Gum Auto first grow

It’s a nutrient defincency, nothing to care to much, natural life cicle of the plant that in the start of the flowering start eating a little bit more nutrient . The signs i can read is Mg definciency for the yellowing not on the veins, the necrosis on the first photo can be Calcium ( related to the Mg)

flushing is an urban myth. Your plant looks a little over-nuted with the glossiness, if true in real life and not the photo tricking me. (canoeing, some tip burn etc.. it's got more than enough) So, you could benefit from a few water-only irrigations. I'd simply resume if it isn't harvest time after that, but with 1/2 strength and go fro there... soil should retian nutrients well, so flushing for 10-14 days isn't unusual. I'd wait for buds to look about ripe, then start. That's typically how long nit takes the trichomes to mature in my experience, 10-14 days.