I noticed more of these tonight on the top of one of the plants. I don’t know if they are new or if I didn’t notice them before. (I’ve shifted things a bit in the tent)
It could be light stress. I had a rough day of work yesterday skipped measuring DLI or raising the light.
It also kind of looks like iron deficiency pictures, the way the discoloration doesn’t cross the veins. Which could go back to the pH issue. If it shows up again, I may need to flush.