Help me diagnose this deficency

These are Jack Herers that are 23 days into flower. Ive looked and cant find a pic that looks like the deformation ive seen in this plant. Its only a few leaves on a couple plants but I want to make sure I head off the problem while its small.

Plants are in a 4x3.5 foot area, 8 plants (think tic-tac-toe board without the center one) under a 600 HPS. Temps are a bit high, ranging from 78 to 95 over the last week (working central air this week) with humidity from 47-90 (have dehumidifier, but I would rather not run it till I get ac in due to heat)

Any thoughts? Am I possibly looking at heat fatigue? Any advice on dealing with my heat issues till I get central air in?

Thanks.

Sorry, forgot nute info. I water the plants twice a week, each plant receives a gallon of water each watering. 1 watering is 15 ml of cal-mag mixed in (botanicare) and the other is following the following nute schedule for flowering.

https://www.rollitup.org/newbie-central/87993-botanicare-dutch-master-fox-farm.html

it looks like heat damage. perhaps move the light up.

Heat damage or nute burn, how hot is your room and how hot is it at the top of the canopy?

By the coloring and texture of your leaves I would lean towards nute OD. Your leaves shouldn't be that dark, glossy and papery.

notice it's just on one side of the leaf, this is not typical of nute issues
the locality and shape of the damage point towards heat/light

my guess would be to over zealous on the nutrients =and/or 2 much salt/sodium, remember less is more.

im thinking heat if it was nute issue it would affect both sides of the leaf, the paper look on your leaves ive found
can be cause by a ph issue, just my 2 cents

What are you feeding them?