Leaf Septoria developping?

Between week 7 and 8 on your diary she took a nose dive. If all the basics are met I would say it's lockout for her to turn so quickly. She does need cal/mag but it won't help if locked out. In many of your photos she's had drooping leaves, could be from having just watered . Just make sure of the basics. lights, temp, humidity, pH, airflow

Looks more like a calcium deficiency to me than leaf septoria. The rusty brown spots on the edges and between the veins, along with the yellowing, are pretty classic signs. Septoria usually starts as round yellow spots with defined brown centers, and it usually begins on the lower leaves, not mid-to-upper like you’ve got here. I’d double-check your pH, especially in soil—if it's outside the 6.2–6.5 range, calcium uptake can get blocked even if it's present in your feed. A cal-mag supplement should help stabilize things if you're not already using one. Also, make sure your roots aren’t stressed from overwatering or compaction, which can also mess with calcium uptake.

If your growing 24/0 then I'd suggest a rest period of 4 or 6 hours of darkness, I'd also on next watering do a slower water with plenty of runoff and measure the runoff ph to see what the actual ph of the grow medium is, you may find that even if your putting in the correct ph it may be coming out way off.

So far you have only used autoflower supermix mix along with a PK bloom fertilizer. grow or bloom mixtures normally do not have calcium and magnesium added as tap water can have enough of both already. Leaving the decision to the grower and how they water. I can tell there is slight salt build up as damage on tips of leaf is from osmosis related to high EC. Flush to remove excess buildup then reapply balanced fert with extra dose of calmag see how she does. It would also help to check your PH if your plant is lacking 2 of the big 3 cations then your PH will most likely be closer to 6, you dont want it ever touching the 5's make sure to keep an eye on that too.

Also für mich sieht es wie Kalziummangel aus, Blattseptorie sieht etwas anderst aus und endet mit schwarzen Flecken. Bei dir sieht es aus wie Kalzium oder was es auch sein kann ist eine Nährstoffblockade, kontrollier doch mal den runoff wenn du eine. Ph wert außerhalb von 5.8 und 6.5 hast oder ein EC wert höher als 2 hast kann es sein das du langsam in eine Blockade kommst. Aber als erste Ursache würde ich schon bei Kalzium bleiben da du ja PK dünger gibst wäre das mit der Blockade als 2 möglich. Also 1mal CalMag geben und als 2 Runoff kontrollieren und gegebenenfalls mit angepassten PH Wasser Gießen ohne Dünger.