Strange visual bug ONLY when compiling source code, not running .exe?

This is a very strange problem… i downloaded some source code and an .exe for importing .3ds models. If I run the .exe it displays perfectly, with no visual artifacts. However if I simply compile the source code that came with it, it works immediately, but there are tiny white gaps along some of the edges of the model! How on earth could an .exe work fine, and then compiling it from the source and running it it would have visual artifacts?
Thanks a lot for any help, I’m truly puzzled.

Maybe the .exe you downloaded wasn’t compiled from the source you downloaded? Or did I miss the point?

or maybe the exe was built in a different mode (Debug/Release)?


… or maybe compiled with a different compiler …

… or the same compiler with a different SP …

… or … or … (and so on)