A major theme of this movie is the solar eclipse, which allows Navarre and Isabeau to stand side by side.....the eclipse happens backwards, though. In a solar eclipse, the moon approaches the sun from right to left, not left to right as seen in the movie.
Actually, there's a much more noticable eclipse slipup. In the Danger on Ice scene, which happens the night before, there's a shot of the night sky, with a 3/4 moon. Of course, the moon would be only a very thin sliver, close to the sun, in the day or two before the eclipse.
the right/left motion of the moon can be easily corrected by facing south instead of north when viewing the eclipse it's all in the perspective, many people think of and look at the sky as if they are facing south. with an object very high in the sky the direction can be seen as backwards. the true motion of the moon is still east to west, we just have no reference on the scene.
First, if you are facing south, the moon would approach the sun from the left as the left would be the east, I think (could depend on type of eclipse?). Second, remember they are traveling, so a 3/4 moon in one place could easily be a full moon in another. Third, there are a variety of eclipse types. You ought to search the internet, it's interesting to learn about.