Near the end of the movie, Signor Naccarelli comes to Mrs. Johnson's hotel and suggests that they walk along the river together to talk. At the beginning of their outdoor walk the sky is light and it is clearly daytime, but within the space of a few minutes, the background sky is suddenly quite dark and it appears to be evening.
On the door mat in the lobby of the US Consulate there's an inscription reading "American Consulate". An official body would, of course, use only the official name of the country: the United States of America - or its abbreviation, the USA.
When Mrs. Johnson walks around town on her own, just before she decides to go to the US consulate, there is, at one point, a clearly visible crowd of onlookers (and a man trying to keep them back by spreading his arms) in the background. There is nothing about the place or the circumstances that could explain their attitude; they are clearly all watching the shooting of the film.
When Naccarelli Sr. takes Mrs. Johnson for a ride in the car, he keeps turning the wheel in both directions, as if there were many sharp turns on the road - yet the position of the car in relation to the camera angle hardly changes, as if the road were perfectly straight. Also, on more than one occasion during the drive he glances at Mrs. Johnson even as he is steering the wheel, i.e. at the exact same time (which, in real life, would have resulted in an inevitable accident).
When George Hamilton sits on the beach next to the woman studying a Russian textbook, the close-up on the book, although blurry, shows that the writing is either upside-down or mirror image-reversed. This could possibly be because the book was not in Russian at all.
As Meg and Signore Naccarelli are driving, he makes a left turn through an intersection. As he does, the carabinieri (police officer) who is directing traffic in the background, is holding his hand up, telling the traffic lane Sr. Naccarelli is in to stop, while directing oncoming traffic to proceed.