Hey alien !
You’re getting a lot of good advice here…Just want to give you my take…
ANYTIME you see your plants exhibiting unusual symptoms (been looking great and you notice issues)
You want to immediately collect some run-off water and check pH/EC (ppm)…FIRST!
If you have high EC/ppm, you are only going to cause more problems by throwing additional nutes at it. I’ve stated it before, but when your EC gets high, you WILL have ALL KINDS OF Deficiency symptoms show up! High ppm raises osmotic pressures at a cellular level, and all the normal metabolic pathways start to break down. This is a death spiral when newer or inexperienced growes look at the nutrient deficiency photos and start making wild ass guesses…You NEED to know where you’re at quickly and nothing will tell you that faster than collecting some drainage water and looking at your pH/EC (ppm)…it really is just that simple…FWIW Bob