The following are active issues for Halo: Combat Evolved as of 4/11/2022 in build 1.2819.0.0.

General

• New - In Halo: Combat Evolved, gamepad look sensitivity when using the "Classic" aim setting is slower than expected.
• New - On Xbox consoles, changes made to the Game Volume options in the Audio Settings menu are not reflected in Halo: Combat Evolved gameplay. Audio volume in Halo: Combat Evolved will instead reflect the default value of 100%. 
• New - When playing with Remastered graphics in Halo: Combat Evolved, gamepad button prompts are missing their backgrounds.
• New - When playing split-screen on an Xbox console, disconnecting a controller may result in the joining player's account being signed out without a notification.
• Unable to Pick up Weapons:
  • The resolution to this issue we have found is for players who are on Windows version 1903 to update their version. If you are on Windows 1903 but do not wish to update, there is also a Servicing Stack Update that will resolve this issue. To learn how to update Windows or install the Servicing Stack Update, please follow the instructions here (Full KBA) 
• Differences from Halo: Combat Evolved, circa 2001 Xbox Release:
  • • We are aware of differences with Halo: Combat Evolved Anniversary on both Xbox One and PC as it relates to the original Xbox release. This is an acknowledgement that we have been aware of and continuously look to investigate areas of opportunity to improve upon the inconsistencies when and where we can in our development roadmap: 
      • Graphical inconsistencies including shaders
      • Holes in Multiplayer maps
      • LAN networking model differences 

Campaign 

• In Remastered visuals on an Xbox One X, framerate drops can occur throughout the Campaign.
• When playing with Anniversary graphics enabled on an Xbox Series X console and at 4K 120Hz, the framerate may drop noticeably in some areas and/or create noticeable screen tearing.
• If the display supports variable refresh rate (VRR), enabling this feature may reduce the impact of this issue.
• If the display does not support VRR, playing at 60Hz will provide a smoother gameplay experience.
• Co-Op Latency issues:
• Currently, we have not been able to identify any issues around this feature and the functionality is on par with the rest of MCC. There is no active development happening around improving/re-writing the legacy network code around this area of the game. Unfortunately, this would be a massive undertaking and isn’t within the realm of what the team can currently support.

Custom Game Browser (CGB)

• A game session may not transition back to pre-game if the session ends up below the minimum player count because a player left during the transition out of pre-game.
  • If the player that left the game was the same one that caused the game to start by joining the session, and then that same player joins again a short while later, all other players either appear invisible or holding no weapon until those players respawn.