What I figured out actually works to break this glitch! I used Xbox 360 not pc so I'm unable to console command or anything I used the resto glitch on a bow just for this occasion. What you do is rest as soon as you get on the summit of apocrypha. My bow was improved to several hundred thousand for damage ( alchemy exploit and enchanted fur armor to have a few million smithing points added) When you finish resting, shoot all three dragons as fast as you possibly can so none are flying and he can't absorb them. But DO NOT KILL MIRAK YET!! Move behind a pillar and enter sneak mode. After avoiding his sight for a while it will say hidden. When that does lean out and shoot him for the one shot kill. It will pass the glitch completely and Hermaeus Mora will appear and you see ending cut scene! Felt so happy after wasting forever glitching at the last battle:l
