The following are active issues for Halo 4 as of 10/13/2021 in build 1.2580.0.0.

User Interface (UI)

On PC, the Texture Filtering graphics option does not impact the in-game visuals.

Please submit a ticket with Halo Support if you encounter this and include media, replication steps, and additional details about when or how this was encountered to provide our developers an in-depth view of the issue.

Gameplay

The “Champion Bundle” forearm and shoulder armor does not display correctly when viewed in first-person during gameplay.
The Covenant Carbine will appear to flicker or flip when starting a sprint.
Gameplay will not be visible when playing on a PC with an Intel HD, UHD, or Iris graphics card.

The intro cutscenes for the missions “Composer” and “Midnight” show momentary flashes throughout the cutscene.
Mission progress resets to the beginning of the mission when selecting Resume Campaign after switching between an Xbox One console and an Xbox Series X|S console.
Several cutscenes throughout the game will not display full letterboxing in the following aspect ratios: 16:10, 5:4, 4:3, 3:2, and any custom windowed aspect ratio.
Player movement may be hindered and result in the player getting stuck around the grav lift inside Covenant deployed lockout towers.
The glowing visual effects on Promethean weapons may disappear or move from their intended locations when reverting to a previous checkpoint.
When viewing a Terminal video in a co-op session, the game will continue to react to input and play audio.
"Reclaimer" mission stops loading or areas of the map are not visible (Full article).

The FOV seen while performing an assassination or using an armor ability is tied to the Vehicle FOV setting.

The “Champion Bundle” forearm armor display as Master Chief’s or Recruit forearm armor when viewed in first-person during Spartan Ops gameplay.
On restarting the mission mid-game, various objects and characters may have incorrect textures or lighting applied to them.
On the mission select page, the mission completion badge does not update or display for completed Spartan Ops missions, regardless of difficulty. Achievements and progression are still awarded.
Completion for the mission “Core” does not show as completed in the mission select menu.

The Trait Zone Properties options cannot be changed when clicked with a mouse, however, the arrow keys on a keyboard will work as expected.