Dying off

Posted this in the Auto forum, but didn't get any ideas, so trying it here.
First time growing autos.
Berry Ryder auto 62 days from seed
Soil mix I've used before and has always worked well
Dynagro 9-3-6 at 1/4 strength every 3rd watering
18/6 light cycle
Temp 75 degrees humidity around 60%
Water ph 6.8
The only plants that are effected are the 2 that I pollinated, the rest are doing fine.
Could this be happening because the plants are at the end of their life cycle, or something else?

I don't know the answer but suspect the plant has all it needs to reproduce and is putting its resources into seed development.

I didn't know what to say either...your at the end of 9 weeks for an auto..it should be ready or very close...the plant is nearing the end of it's cycle and appears to be yellowing naturally...however flowers didn't have a chance to finish for whatever reason. I suspect, and you say it's always worked, but a 9-3-6 feeding throughout is not a good balance once in flower! Excess nitrogen, even if your leaves don't show excess symptoms of it, can delay, suppress flowering.