She looks good.
Suggestion, take your plant that's having issues. Run a couple gallons 5/5/5 (5 Mega, 5 Cal-Mag, 5 Silica) at her until you get some runoff. Check that runoff with TDS tester. Compare the runoff ppm with ppm of a gallon of 5/5/5. You're looking for the stuff that came out to only be a couple hundred points over what went in. If it's significantly higher, you have build up in your growing media. If so, add another gallon of 5/5/5. Test some of the last runoff from it. Is it within a couple hundred points now? If yes, stop, you flushed out the build up. If no, keep going. A mature plant shouldn't be having an issue with N toxicities at the 5/5/5 level.