It does work. It's been proven to be in the game's coding; in fact, it's possible to prove it.
The games run off a random number generator, which controls shininess (as well as nearly everything else). It's possible to force the RNG to be at a specified state by changing the clock on your DS and carefully timing how long it takes you to get from turning it on to pressing 'Continue'. If you do this, you can make international parents produce a shiny, but same-language ones produce a normal Pokemon with the same RNG state (but not vice-versa). Therefore, there is something in the game's coding that recalculates the egg's stats if you use international parents (until you get a shiny).