Boss battle glitch or something

I just wanted to say i throughly enjoyed this halo compared to 4 and 5 but there are still alot to work on especially on all the plot wholes left like about what happened to atriox and cortana like we know they died but what happened and to the other spartans like i know they were hunted but come on none of them survived. And on the boss battle with tremonious it took me like 2 hours to do but im not complaining about that it halo its suppose to be hard to beat but there were about 5 or 6 occasions where he had no health left and i still ended up dying, like i said i dont mind that it was hard but the fact i had to restart it so many time because he had no health left was so annoying! I have pictures and a video to prove it but the website wont let me post them