No, that was my take away from my plant. I was hovering, second guessing, and made a change I didn't need to my feeding schedule and I can see the slight set back. All I did was fed half my normal strength 1 time.
Your plant looks like, if anything, P from npk is the one that stands out most on the deficiency links. Idk, I feed around 1.8 ec ph 6 going in.
I don't really check ec, I just use the tsp measurements. Like a lot of guys using smaller lights i half the recommendation per stage of growth.
If you want to learn to diagnose, take a look at the link in my sig and make up your own mind. Then go from there.
Advice is great, but you have to compare it to your situation and see if it really applies.
Environment is very important, vpd in range, light height and leaf temp to air temp diff. 5 degree f btw.
The leaf is basically the wet bulb in this scenario. But lights too low can make that too high. Or too far away not enough temp diff.
You will get a feel for vpd enough to notice the way outside plants are effected by it during different weather conditions.
Ac infinity controllers now have vpd stuff built in or you can get a free phone app. It just tells you what temps and RH are the most conducive to growing anything.