According to the team, its 'RICOCHET' anti-cheat software suffered "an issue with a detection system" last weekend, leading to "a spike in cheater reports". This issue has now been resolved, and things should be returning to normal as we speak.
Here's Activision's full statement on the matter:
"RICOCHET Anti-Cheat resolved an issue with a detection system over the weekend, which resulted in a spike in cheater reports. For clarity, #TeamRICHOCHET is able to detect the specific platform for all users, despite how they may appear in-game.
If you suspect a player in your lobby is cheating, regardless of platform, we recommend you submit a report in-game for further investigation. We remain committed to combating cheaters, shutting down cheat vendors, and providing our players a fair and fun experience."
If you're yet to try out MW3 on Xbox Game Pass, it's worth reading over our installation guide before downloading the title. The 'Call of Duty Hub' makes things a little confusing, so, be sure to check you only have the files you need for Modern Warfare 3.
Despite a bit of a dodgy install process, Xbox Game Pass is now delivering some neat bonuses for players, like discounts on COD Points and DLC packs thanks to subscription benefits.