5 weeks into flower, need help diagnosing. Problem ongoing for 3 weeks :(

Hey guys, ive got a mother plant 5 weeks into flower. I have been having an ongoing problem for 3 weeks. Here are the symptoms i am dealing with, followed by a brief timeline, and a couple pictures.

Symptoms :
- Middle and Upper growth leaf tips yellowing, turning to browning/drying
- Leaves go from yellow to brown, leaf tips pointing up, vein of leaf remains green.
- Larger fan leaves damage starts at the tip, and progresses on the outside edges, eventually working inward. The center vein again remains green.

Growth is still occurring, but i am losing alot of fan leaves.

Heres a 3 week timeline :
- 3 weeks from today: i think the plant suffered from an overfeeding ( NPK liquid fert + alfalfa/worm castings/kelp extract.
- 2 weeks from today: I recognised what i believe was/is Nutrient Burn. Instead of flushing i decided to just stop feeding nutes until the condition improves.
- 1 week from today : Condition has improved only slightly. Still experiencing symptoms of nute burn.
- Today: Leaves are still yellowing, and eventually dieing, Rate of leaf loss down 50% versus 21 days ago.

Heres my question to the viewers
- Is this Nutrient Burn/Overdose as i expected, or is it a nutrient deficiency? After not feeding nutes for 3 weeks i am starting to wonder what my next step should be.

Heres a couple pictures, pics are 5ish days old.


Thanks for reading. Please help me diagnose.
If the consensus is nute burn ill flush with my prepped water supply.

Grow room environment factors:
Temp 78-82 - humid 45-50 - 12/12 lighting - Soil grow, Roots organic/perlite

Sounds like mild to severe (Mg) def, read and compare ... the bit about yellow leaves ,...green veins is the tip

Hello. Thanks for your response.
That description fits well. I have never added camg or salts, ill try 1tsp salt/gal next watering.

Thank you very much.
I was on the verge of flushing tomorrow.
Im glad I asked lol.

Will post a new pic in the morning.