Males don't show first,
you can have late showing males and herms.
....
If they don't show after a few weeks I kill them.
I also understand what you are trying to say, you just missed on how you said it...
Usually, it has been my experience that 70-80% of males show their sex first...
That leaves 20% to fukk you up later...males do not "Always" show first... just 70-80% of the time...
Also, a Hermie, is not a male... it is a female which turned Herm....
Bagseed genetics... could be, and do anything...
I have had a Female [bagseed] very nice and healthy plant, with no light leak or stress...
Turn Hermie 6 1/2 weeks into light change [12/12]...
With a Herm, you never know, and there are no hard/set in stone rules... except beware....
Another time, I cloned for sex, a switched it [to 12/12] with first sign of root... grew out, and no problem...harvested...at 9 weeks...
Then I took a clone again from this plant, and it herm'd on me...
I thought Fluke...
I had already cloned the mom, about 20 times...
So I put her into 12/12 right after a small clone of it...
The clone popped out some mini nanners... sheiot...took it out and killed it...
Then looked over the mom, with 6 1/2 weeks of good bud...wait one more day...
Next morn...
At least 50-75 nanners had popped out !
This in a 4x5' grow room...
Fukk...
Killed the mom, and all 20 children...
Lesson learned, if you see a nanner, you could be Fukked....
I was able to check the date of nanner, and sure enough, I had some calyxes get some seeds, maybe around 40-50....
ONLY, the buds that were viable with hairs, and plants in bud room for over 10 days...got seeds...
So out of 20 potted plants in Bud Room, I only got seeds where the buds would take the pollen in...[5 of 20 got seeds]
I really thought I'd caught the Hermie in time... over night nanners... look out!
And Good Luck!