Braune flecken und Punkte

Without an EC meter, it'll be hard to guarantee what the issue is. However, one of my current plants seems to be going through an almost identical issue to the one you're showcasing here. I also opened a Grow Question about it and have come to the conclusion that it is either: A) Fungal related, more specifically Leaf Septoria; however, just like in your scenario the spots on the leaves didn't start at the bottom of the plant, which may indicate that it is instead: B) Nutrient lockout on varying levels. Could be caused by either deficiency or excess nutrients. Best way to diagnose the specific types of lockout would be to first use an EC meter, but in your case you can use a chart like this: https://loudclouds.co/wp-content/uploads/2016/07/marijuana-deficiency-chart-jorge-cervantes.jpg, though note that even charts like these aren't fool proof and merely a guide. When your other autoflowers of the same strain don't show any symptoms, it's often due to phenotype. On the bright side, even if you were encountering either of these issues, your plant seems to be approaching harvest time and the buds look great! So all in all I'd say you don't have much to worry about. Incase it is leaf septoria though, make sure that no nearby plants also start showing spotting symptoms, if they don't show any it was more than likely a phenotype issue with the strain as you previously mentioned, though noting if it's excess or deficient is REALLY tough to do without an EC meter of sorts. Best of luck to you!