When Doctor Vando and Dutch meet in the bar at approximately 30 minutes into the film, there is a closeup of Vando's earring. At the end of the scene as Doctor Vando leaves the bar (approximately 34 minutes), Vando points at his earring. This time, the earring is considerably thinner and smaller.
When Dutch is in Fedora's bedroom browsing through the notebooks filled with "I am Fedora", it is obvious that the written pages are all copies of one another.
In the 2013 restoration, Stephen Collins is credited as playing "Young Berry," not "Young Barry," and Michael York is "Micheal."
At minute 32, when Dr. Vando is shown the film script, he reaches for his reading glasses and reads the title. He shouldn't have to use the glasses because as we have seen before the title is printed in very large characters.
In the opening scene set in France in 1977, a woman throws herself in the path of a steam train. The last steam locomotives on mainline French railways were withdrawn in 1974, so this could not have happened as shown.