Is there some Kind of new bug where you cannot see your arms/hands and weapons?
It happened to me twice on Darkstar/Firefight, to friends as well.
https://www.halowaypoint.com/de-de/games/halo-5-guardians/xbox-one/game-clips?page=1&gamertag=HerrMittmann#ugc_halo-5-guardians_xbox-one_gameclip_HerrMittmann_a11b9eac-b736-4c56-8d80-8ab30492a51e
Both times right at the beginning.
And on Stormbreak/Firefight this happened to a friend alone:
https://www.halowaypoint.com/de-de/games/halo-5-guardians/xbox-one/game-clips?page=1&gamertag=MusikerBoot99#ugc_halo-5-guardians_xbox-one_gameclip_MusikerBoot99_69b64dc5-2471-459b-844d-57f71b23ce11