Launcher still wants to download patch, even though it is already loaded

I updated Minecraft to 1.7.4, so that I can seize the twitch integration. I installed it, and logged out to play another day. When I came back, the launcher didn't recognize the fact that my computer had already installed 1.7.4, and still said "Ready to download & play 1.7.4." There is no affect on game play, but this should not happen.