brown dead spots on leaves

so this is my first grow. week 6 of flower 2x2x5 tent. 150w led 42w clf. fox farm nute system. happy frog and perlite 3 gallon smart pots. opened the tent today and found brown dead spots on some fan leaves. is it light burn or a ph issue or nute burn. what do you think it is and how do i correct it.

where abouts on the plant are those leaves?
Is it some leaves, most leaves or all leaves?
How many weeks flower should they be getting?
Have you tested the soil pH?
If it's not pH IMO it's cal/mag def but minor
I'd expect light burn to show in bigger patches . . . unless those leaves are bigger than my face

the leaves are close to the top of the canopy. im growing sugar black rose supposed to have a 53 day flower but i stunned my girls in week four so they are a little behind. ph tester came in the mail today ill check the ph when i get home. the spots are on some leaves

soil ph was around 7. ph'ed water and flushed.

You're getting tip burn also. Back off the nutes a bit.

only a couple of weeks till harvest so flushing and no nutes. thanks.

this close to harvest there's not much you can do, it's a know for next time you grow it a touch more mag/cal if you're blending your nutes if not accept it's a sign of stress coming close to harvest