Magnesium?

I'm thinking magnesium deficiency, but I've been using CalMag per feed chart.
2nd into 3rd week of 12/12.
ProMix all purpose with perlite.
GH Flora trio
SF1000 with two Bloomspect 300's.
Temps are 75-78 light and 65-68 dark.
Humidity around 55% on average.
32x32x60 tent with plenty of wind and air flow.
I'm feeding by this chart

Currently about to change from transition.

The problem is on fan leaves at the bottom two internodes.

I just got done with a full flush and light feeding about two or three days ago (I flush every other feed). I'm usually having to feed/water about every week.
I haven't been checking run-off ppm or pH. I know I should, and I will from the next feed on.

Ya bud check your ph in soil and nutrients. When you say flush are you soaking the shit out your pro mix till you get run off. Might be getting too wet all the time? How big are pots too plant? They drinking good?

I agree; the leaf examples look short on Mg. Epsom salt will help, so you're not bombarding them with the added N during flower, from the Calmag. Good luck.

I should clarify... I was baked.
When I feed, I use a gallon of plain distilled water followed by a gallon of the nutrients solution. I get about 1/4 runoff by the end. To flush this last time, I ran 3 gallons of the same water. Then I put a gallon with half strength solution. That may be the wrong way idk.

It's a 3 gallon pot. The plant is drinking good in my opinion. The lights just came on and judging by the pot weight it'll be time to water again in maybe two days.

Should I sideline the CalMag and just use the nutrients solution with added Epsom salt this time?

I try to avoid any further N inputs once I hit flower, so yes, if it were me, I'd use Epsom and leave the CalMag out...unless you think you need Ca. Slow and steady wins this race...good luck.