What is causing my leaves to look this color?

Any idea what this may be? I have never had leaves look this color before.

I'm in week 6 of flower, growing in soil in 5 gal pot. Feeding Mega Crop and 5ml calmag ever other watering at 800ppm. Run off is at 6.0ph. running two 100w qb led in 2x2, 12" from tops.

Nutrients?

Here are more pictures of the whole plant...

From the last set of pictures ... the new leaves are not showing those colours. It's only on the larger fans further down

The same thing happened here a few weeks ago. I had just switched to 11/13 that morning - then temps went down to to high 50's overnight - something you do not expect here in mid to late June. Not expecting those chilly temps, we didn't have our heat turned on. It was pretty cool when I woke up that morning and those cool temps sent them into late flower panic mode overnight. Plants go looking for phosphorus in that scenario but I hadn't provided any bloom nutes yet so a lot of the lower larger fans turned that purplish-brown colour and the plants looked a little droopy. The lack of heat created a short lived phosphorus deficiency.

Once I got the temps up, the plants looked healthy again after a few hours. I could start them on their bloom nutes. And none of the new leaves since that time have shown those colours. Those discoloured leaves won't turn green again so I removed the vast majority of those brownish leaves.

Did you have a night or two where the temps were chillier than you anticipated?