finished??? mixed signals

Hey guys, i have a question for the more seasoned growers. I have numerous strains going, but my favorite keeper puzzles me. It seems to take forever, but is also fast. What I mean is I can harvest at 70 days, and end up with smoke that is better than most. 90% brown hairs, but no signs of fade. Now if I let her go longer(currently approaching 90 days) I see signs of fading, but she starts putting out fresh white hairs. I have plenty of strains that follow all of the basics of harvesting. This one does not. It just does not seem done at 70 days, but after that seems to get a second wind? Anyone have any insight as to what i am dealing with here? The easy answer is to harvest at 70 days if its still top smoke, but i want to know if I'm missing out on something magical by not letting it go way longer.

I had a train wreck that did the same thing back 7-8 years ago.I read up on it. I'm not sure of the tech term,but,some strains do that because they want to reproduce. Leave it too long it will pop male flowers.

I always assumed that if you get late growth like that it means it's at risk of going hermie. I tested a GSC by letting it go an extra 25 days in flower and sure enough, male flowers started popping up at which point I cut it down that day. I was trying to see if I could make it go heavy on the amber trichomes and get a more indica effect for this particular strain of it. It definitely does not have the buzz of the ones I harvest at ~10 weeks.

You are both on the money. It will start to pop male flowers if i let it go too long. I guess she is just trying to pass on her genes. Thanks for the replies