You're thinking deficiency. ? I've been adding in 1 gr/gallon of Epsom and most folks said that the newer 321 mix doesn't need it, I can push it up a bit since Epsom is subtle and see if that clears the spotting. I appreciate the input. ?
I don't know anything about 321, but by the pic I was thinking your spraying Epsom salt on those, but when you zoom in your tips show difference, that 1 yellow leave is starting to tell you that plant isn't happy with water.....
If it was me I would add some to your mix and see what happens..
If this has just happened in the last week , I think it has 2 do with this new moon we had..
My indoor plants went crazy on growth in 48hrs cause of it...
Anyways this is just my 2 cents worth...