Mag deficiency?

I assume this is a magnesium deficiency but my question is do I correct it? The other plants are not showing signs yet and am only around 14days left of flower so is there any benefit in making a different feed when the other plants look good and so little time left

I would lean more towards calcium and magnesium than mag alone, but if you've only got two weeks left a change in feeding would probably be more wasteful than restorative. From the look of that leaf, I'd just pluck the bad ones and let her roll.

Yea, probably best not to overdo things so late, but might still be helpful fine tuning it, atleast for future.
Would help to know some background on medium and nutes shes been feeding.

But I'd opt for potassium issue since the symptoms seem to be leaf edge heavy. And deficiency.
My bet is potassium deficiency.

Mg deficiency should have some interveinal chlorosis or/and cupping of the leaf. I can't see either.
Calcium also competes for the same ions as Mg and K so it's important not to just add more, but to consider the ratios aswell.
So check what u've been feeding and my guess would be little heavy on the Mg and maybe Ca and should go higher K to Ca/Mg ratio.

Greennes could ofc be plenty of N, but can't see much burn on tips.