But why would the ship appear to be in two places at once? Even if it moves FTL, the light reflection from its first location stops the instant it moves to a new location. Even if there was a delay in the reflection from the first position, there would also be a delay in the light reflecting off of it at the second location.
this sort of really briefly works if the observer is nearer the new location. Light from the new location reaches the observer before the lack-of-light reached the observer from the old location.
still would only work for the tiniest amount of time and confuse no-one, but then this isn't hard sci-fi.