It's so short-sighted just to juice up a November PPV. They're both hurt/injured. Cormier still has money fights with Brock and Jones around the corner, so if he gets caught slipping that hurts both of those. Black Beast JUST climbed out of the toilet with that wack Nngano fight, and with his recent spike in mainstream popularity, you can play that out a little longer. If DC merks him he's back to square one, whereas he can become the heavyweight attraction once DC retires.
And again, they're both hurt. UFC must be hurting for bread.