When Jane returns to the Antique Shop (minutes before she falls into the canal), as she is crossing the bridge, the camera pans to the shop, and the red goblet appears in the window. Moments later in the scene the goblet is gone, and there is a silver candelabra in the window.
When Jane gives Mauro a cigarette in Campo San Stefano, she does not light it for him. He appears to have no means of lighting it, unless he has matches in his pocket. Yet, a split-second later, as Jane is walking away, Mauro is puffing away on the cigarette.