Those with data caps, you may want to stop playing until a fix is implemented.
Halo Infinite multiplayer

If you are still enjoying Halo Infinite's multiplayer mode, you may be upset to hear that something has gone terribly awry with how the menus download and cache data. Or rather in this case: How that data is not cached.

Twitter user @NicmeistaR seems to have discovered that Halo Infinite was downloading a lot of data. He saw that just one match of Halo Infinite multiplayer ate up "305mb" of data. It is unclear if they mean megabits or megabytes. He says that after about two matches of play, the amount of data downloaded could be in excess of "1GB" of network traffic.

Initially, NicmeistaR believed the data was being downloaded during a multiplayer match. As it turns out, most of that data was downloaded while simply sitting in the game's menus between rounds.

Another player going by the Reddit handle wowisthatreal did their own investigation into the matter. Using network debugging software called Fiddler, the Reddit user made a downright shocking discovery.

They found that in between gameplay rounds, Halo Infinite downloads the Season 2 banner image "about 1,000 - 2,000 times." This can bring the amount of data downloaded to the 1 to 1.5GB range. The user says that downloads do stop while you are in a match but will resume after the match ends and you are returned to the menu.
Another Reddit user, SenatorObama, points out just how easily this could have been avoided.

It means that, either:
  1. The server isn't putting caching headers on static resource-type responses as appropriate.
  2. They somehow managed to use a fucking HTTP client library that doesn't respect those. Or they re-create the HTTP client regularly instead of re-using one.
It's just fucking amateurish across the board. It's totally fine to rely on HTTP server/client caching... if you fucking use it. Jesus Christ 343i, come on.
Update: The good news here is that 343 Industries does seem to be aware of the issue. Senior Community Manager at 343 Industries, John Junyszek, posted on Twitter that they are "looking into it."