The following are active issues for Halo 2: Anniversary as of 10/13/2021 in build 1.2580.0.0.

Campaign

New - In Remastered visuals on an Xbox One X, framerate drops occur throughout the Campaign.
Rarely, the game will kick both players from a co-op Campaign session after they skip a cutscene in remastered graphics.
Terminal videos default to English only.
Subtitles are not present in gameplay.
Subtitles are out of sync with the audio in cutscenes.
Cinematic audio for Halo 2 and Halo 2: Anniversary is affected by different audio options.
Pre-rendered cinematics and Terminal videos can have visual issues in non-16:9 aspect ratios as they were rendered at 16:9.
When the Scarab Skull is enabled, gunfire sound effects are missing from multiple weapons.
A hard lock can occur upon firing the Plasma Rifle when the Scarab Skull is enabled.
After destroying a Sentinel, their lights are briefly visible before disappearing.

Halo 2: Anniversary Multiplayer

Any camera turning caused by a view angle restriction while in a vehicle passenger seat will stutter above 60 FPS.
Some pixilation is visible on shadows.
Performance lowers during games of 3 Plots.
Some maps have areas where texture resolution appears lower-than-expected.
When looking at the fan on Stonetown, the framerate sometimes drops to 45 frames per second.
Lighting is inconsistent between Elite and Spartan armor.
The Hoplite armor is missing a rear armor piece in gameplay.
New - When using “Any” or “Team” voice chat options and one player is speaking, voice chat icons appear over all friendly players instead of only the person speaking.

The Trait Zone Properties options cannot be changed when clicked with a mouse, however, the arrow keys on a keyboard will work as expected.
Halo 2: Anniversary Multiplayer films are capped at 60 FPS even when the unlimited framerate option is enabled.

New - In the Extras menu, all dialogue in cutscenes for Halo 2 Anniversary is aligned to the left audio channel.