I have read about this bug months ago, but didn’t think it was still in the game. Basically:
After you go up into and destroy the large unknown Covenant ship and you start moving again, the ground will be completely gone a little ways down the path. After Cortana stops talking about Rampancy and the Nemesis stops, it disappears and I die.I have tried reloading the Checkpoint and Save and Quit and then reloading from Resume and it still does it. I don’t know if there is a way to fix it apart from just reloading from Missions. But I don’t know if that will mess up Campaign Progress or not. It sucks, because this is the only real bug I have encountered in all of the Halo Campaigns in The Master Chief Collection.