When Vinnie goes up to the motel desk and rang the bell repeatedly, the clerk turns around. The clerk is wearing a solid white shirt. The camera goes back to Vinnie. When it goes back to the clerk he is wearing a white shirt with blue stripes.
When the clerk first turns, he's at a bit of a distance (not super far, but definitely in the background of the shot), in an area with less lighting than the foreground. That makes it hard to distinguish the light blue from the white stripes. But if you look close, you'll see that it IS the same shirt throughout the scene.