Strange yellowing of leaf veins.

I am having the weirdest yellowing occurring on my Pineapple Express. It’s 6 and a half weeks into flower. It’s the only plant out of 4 showing anything like this. Now I’m doing 8 plants and they are 3 and a half weeks into flower and two of them are clones off this Pineapple Express and one of them is showing the early signs of the same yellowing. Can anyone identify. All my other plants are looking great and none of them including this one have any nutrient burn. They all look very healthy except this one. Please help.

The yellowing is starting at the leaves veins mostly on leaves that are receiving light.

how close are your lights. wattage and type?
if not burn id suspect iron manganese def likely a ph issue

They are 20 inches above the top of the canopy. The soil tested 6.5ph 12 hours after my last feeding. It’s the only plant out of 8 this time showing any problems. I’m using a 200w actual power consumption led full spectrum.

The light above it is the 200w actual power but the lights for the plants beside it are 300w actual power led.