Is this a deficiency or excess of nutes?

If confused, more likely than not it is lockout of some sort... you also mention others have slight burn... so you are probably at the upper edge rather than the lower edge. without knowing what you put into your substrate, it's difficult to say. Calculate ppm from your guarnateed analysis labels. add them up per element... compare to other formulas out there... e.g. i have one posted each week in my diaries. Now, i am soilless. I feel 100% of plant needs all the time. In soil, you either ramp up to that or you have some sort of living soil/super soil situation going on. That'll be a different formula mix, but the end result will still be similar in the substrate. Re-callibrate your ppm pen.. maybe it is off? Consider recent behaviour.. if you can eliminate overfeeding, you can simply refer to a leaf chart and deduce what is going on.. when the symptoms are messy, it's more often lockout in my experience. You could be light on some things and excessive on others... and each plant can be different, so treating them all the same doesn't always work well.