Should I worry?

did you change your formula? that would have a bigger impact than light schedule change and the first thing to assess. could be start of k-deficiency. or a molybdenum deficiency -- which if it is Mb, more likely pH-caused or nute lockout as it is rare to have a trace element issue (Mb). These are the only things that progress around the serated tips like that. ph/lockout always a possibility for any issue seen, but in these cases you usually see more than 1 symptom at a time unless a very minor imbalance at play. phosphorous and potassium have an antagonistic relationship. i didn't do the math but eyeballing the addition to 10-30-20 in lieau of 15-5-whatever could have caused this... you'd have to calculate the ppms of it all and see just how high did P go? if 100+, getting near a point where it will lockout other stuff, i'd wager. just because a symptom didn't occur immediately after a formula change doesn't mean it wasn't caused by it. the longer it takes to reach that new euilibrium just means it was off by a smaller amount. any formula change will take a while to flesh out equilibrium, even if you have fully transistioned the substrate to teh new formula.. the metabolism of the plant is the key here... however tha tplays out over time.. fewer symptoms /slower progressing jsut means you are closer to a better formula and only minor adjustments needed to get there.