If temps didn't drop low at night or similar... it's possibly over fed. Too far away from harvest to call that senescence, in my humble opinion. some plants are more prone to it.
you've got ~3 weeks, make that canopy last. bit too early for a nosedive. I have a nut calculator you can use to look up all your products used and the resulting ppms added up for you. Links in my profile comments
So, consider recent behaviour.. if the "bloom" formula dropped N too far, you liklely need to boost that.. if you see issues elsewhre, you can make more informed decisions as to what to do in your context.
+1 strain
