I look at it as inevitable , it is going to happen.
Even running as low as I run, it happens.
One thing I plan of changing next grow is in flower, day 21 pruning, I have not been lowering my nute rates and also keeping the same irrigation schedule. I believe that I get a minor lockout due to the plants not needing that much nute input after the defo. I think there is a buildup of nutes in the root zone.
I normally do not check my runoff but when seeing more tip burn than usual I checked it this grow, it was 760 ppm, 260 ppm more than I was feeding at the time.
Next grow I plan on backing off A&B at day 21 for at least a week, giving the plants time to get some growth back.