Plot hole: If the curse counts an eclipse as night, then Navarre should have turned into a wolf during the eclipse. If the curse does not count the eclipse as night, then Isabeau should have remained a hawk. In neither case would they both have been human at the same time.
Suggested correction: That is the whole point; it is neither day nor is it night. Each only suffers the curse when it is specifically day or specifically night. Any time it is not one of those two events, the curse is not active, as shown earlier in the movie when both are human for seconds during a time in between day and night.
Factual error: The hawk that Isabeau turns into is a red-tailed hawk. Red-Tailed hawks are a North American Species and wouldn't be found in Europe.
Suggested correction: There is nothing in the film to suggest that because they live in Europe, Isabeau should only turn into a hawk native to that continent. It's a magical curse. A film can make its own rules how magic works in their universe and in this film Isabeau is cursed to turn into a North-American hawk for whatever reason.