I have a 2007 C50T, and Mine does that all the time! I just ease out the clutch to hear a click in the trans, then kick 'er down, and it will shift while at a stop. If you are in 5th, you may have to do it a few times to get to 1st, it is common. My Vulcan did the same thing, and my uncle's Volusia does it too. I never have problems down-shifting while moving, it is only when I have to stop fast, while in a higher gear. It is common with a lot of motorcycle transmissions, especially these continuous mesh type... Nothing to worry about though.