I use a MacBook Air running Windows (Bootcamp) which means my keyboard layout (Danish) is a little different that usual. For instance, I can write @ and $ the same way one would in OSX. Which I like I've never experienced problems with this anywhere, but Sublime Text drops back to a standard layout after having been open for a while.
I have not been able yet to find a pattern in the behavio and the console doesn't reveal anything. It's very annoying since I suddenly need to change which keys I use or, as an alternative, restart the program.