Might be getting/having an issue, but what?

Spotted some discolouration on the edges of the leaves
What might this be

Where are these leaves located?

Details of your grow?

Dank Bongula said:

Where are these leaves located?
Details of your grow?

Click to expand...

On the plant but for picture purposes on the laptop
Seem to be the higher leaves ... the bottom ones have no markings
Could, imo, not be lightburn as we are talking two blurps 50cm from canope,
I do feed some 1-5-1 and 1-2-3 (6-12-36) every other day but the concentration should be low enough for every feed (I am going at 3/4 strength)

I am in bloom , well they are , and according to my other post about 4 weeks from harvest

2 Auto AK45's about 70 days in their grow. Started of in the soil of a tomato grow back (compast)
Feeding schedule
151 - dry - 6-12-36 - dry - molasses dry , repeat

That looks like nutrient burn.
Why I think this?
Your leaves are quite dark too.

Pic of the whole plant?

May want to back down the nutes a little. Lights at 20in should be ok, what's the power though? Just to be sure...