Yes this is what happen to me as well. No big download whatsoever after using the disc to install the game, 30 minutes finished.

Another thing to note is that did you guys update the original game before this. Wings of Liberty had a big update recently 4-5gb if not mistaken, maybe bigger. Problem with the update is that it doesnt show on your progress screen like the optimization update, its kind of hidden and you guys need to check it from the download option instead. So what most people did is that when the progress bar shows the optimization update is complete they closed the launcher because did not notice this. I myself only found about this after reading here in this forum.