That's not quite right. Obviously any time-based DRM lock would have the software check with the OS how long it has been since the console was last online.
It may be that the console-level DRM is off, but there is a software-level option that has been applied (whether temporarily or not) to CoD.
Yeah, there seems to be too much stuff possibly at work to really get to the bottom of it for now. Guess it's just time to play the waiting game.
I feel like MS would have immediately been aware of something applied to the game at large, however. Instead of 'looking into it'.