The following are active issues for Halo 3 as of 4/11/2021 in build 1.2819.0.0.

User Interface (UI) 

• Some keys cannot be bound when using non-English keyboards
• Some players receive an error stating, “One or more actions are not bound to a key” after the game updates or when switching between the Halo Insider and Retail builds. 
• We have improved our reporting of missing key bindings by adding a per-title notice when another title has actions unbound. While we are still investigating causes of this, it is recommended to run “Restore Defaults” at the “Controls” setting page if you still encounter this issue

Gameplay

• The Battle Rifle’s lights turn off when equipping S6 weapon skins.
• Player emblems do not display on the new Season 5 right-side shoulder armor pieces.
• The throw animation does not play when deploying equipment while wielding the Automag. 
  • Our team is aware of this and continuing to investigate potential causes and fixes for when this occurs. We hope to have more on this in the future.

Campaign

• 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.

Multiplayer

• New - When playing with a high Field-of-View (FOV) value and the effects quality option set to Low, some visual effects on the Halo 3 multiplayer map Waterfall may not appear.

Audio

• Non-English language announcers are much quieter than the English announcer.

Forge

• The Allow Editing spinner and all options within it are written in all capital letters.