Issue with my fans?

Hey guys any help much appreciated.
I'm not sure if this is a lockout/deficiency or nutrient burn or worse.
I'm growing in coco + perlite mix using nutrients at around 2.0 EC, ilgm Jack herer strain.
Most of my plant is fine except for a few fans with these markings, plants are about 7 weeks into veg getting ready to flip now.
I haven't flushed my coco since day 1 not sure if that's the problem, ive never encountered this issue I've recently dropped my nutrient to 1.6 EC.
Thanks for your time

Don't the excess green give u a hint..?

flush and no nutes for 10 days

or until you see any improvement

good luck

please do not flush,how can any body say flush with one pic,LOLbetter pic would be nice ,but please don't flush, just back off little bit.