Start of a deficiency?

Hey RIU,

Normally I'm pretty good at this shit but bit stumped to what deficiency this is. Have searched but not sure. Some expert opinions be great.

400w Duel Spec
PH: 6.8
Soil
11l Pots
Bio Grow during Veg
Today is 4 days into 12/12.
Strain: Humboldt Fem.

Topped for 6main cola.

Any opinions on the pics
The lightening is only on the newest growth as you can see....

Maybe im too easy but they look fine to me! New growth looks a tiny bit light but all in all I wouldnt be worried if they were mine. Obviously it would lean towards N deficiency but if you know your feeding proper let it go.

To be honest normally nothing fusses me! This seems to be a great grower so wanted a nice big yield off it. I fed Bio Grow in veg and its latest watering yesterday just plain water. Next feeding when dry probably start low dose of Bio Bloom.

Thanks for your opinion man, + REP.

ive had that a couple of times when the temps fall a little at night but it was never anything to worry about!

Cheers. Wasn't a major panic just thought this gone bit lighter then previous grows of different strains. Could be the cold night temps or genetics or mix of both I guess.
I know is fairly cold compared to lights on temps. I am manually putting her into 12/12 as got a NL still in veg and 2 Auto Pineapple Express going too.
Get up 8am and take her into the dark and 8pm in evening goes back under lights