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?
