There is a major glitch on the 2nd to last warp teleporter, before reaching DENDRON.
It glitches so that when you teleport it throws you straight into the wall, killing you instantly!
Once it glitches out it does this for all fireteam members, and so the whole nightfall had to be started again from scratch.
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Bungie are aware and investigating, please see this Bungie post: https://www.bungie.net/en/Forum/Post/242928205/0/0