Game modifies time/date settings

[tranx]

I believe it comes from Civ5 itself and not Steam because I play in offline mode. Yesterday the game changed my time settings to GMT. Today it changed the date to 27th. The strangest thing is that changes occur either on Windows7 or on MacOs - I run Civ5 on bootcamp - despite the fact that I locked the time and date settings on MacOs. That's kind of annoying and also slightly confusing.