Read this elsewhere as well, but there seems to be no discussion on it.
Started a new game on realistic mode. First part of the first level (Mexico) played through fine, definitely on realistic mode. I shut down my console, loaded my game back up later, and now the game is on Normal mode. Obvious as the crosshairs turn red when they're over an enemy, and I can take a crapload of bullets before I die.
This is quite a massive oversight. Anyone else experiencing this?