...well, with that flush you're short on nute's more than ever, hence the worsening,... don't flush unless there's a good reason for it, and never with the "supersoil" layered set-up! I don't think it's a good combo the use nutrient poor soilless on top of a rich soil, too different, and you'll still need to feed a the seedling/young plant for a bit before it taps into the rich layer,.. this makes balancing your inputs more dicey,... use a true soil if there's a next time, and BTW, use KindSoil at your own risk! I've seen lots of issues with this soil, which I was on the test run team for,... and since, troubles have been more frequent! Looks up the KS section here and see what's happening,... some are OK, others not so much,...
...your dosage is pretty weak on the nute's, are you going at half strength or less? I'd ramp that up across the board... pH looks great! ...CC- symptoms look like P and N defc., maybe Mg too,... more food, and don't let the medium dry too much, never to wilting especially! Some moderate cycling is fine, but nothing too extreme,... Lemon looks mostly like N defc.,.. Now, some of this fan reserves consuming is normal at this stage, so don't sweat it if they don't correct much, if at all, particularly the lowers,...