A curious occurrence tonight:
Threads on NeoGAF and the official Halo forums allege that Halo 4 players are being banned when trying to play the Crimson Map Pack.
343 Industries responded in a thread on Halo Waypoint:
We are not permanently banning players for previewing or purchasing the Crimson Map Pack. We are currently investigating the recent reports of permanent matchmaking bans.
We will provide further updates tomorrow. Thank you for your patience.
The Crimson Map Pack was originally supposed to be available exclusively to Season Pass holders, or those customers who bought the Limited Edition of Halo 4. However, when the time came, the was available to everyone, for free.
Microsoft and 343i admitted that this was unintentional, but rolled with the punches and promoted the “14 Day, Buy and Play,” offering six Specializations and access to the Map Pack until today.
The ban appears to be impacting those who are playing (or trying to play) under the promotion as well as Season Pass and Limited Edition players.
We’ll update you as more information becomes available.
Source: Halo Waypoint