I have the same issue, and all of my movies are VOB format. I just did a batch rescrape to update the top 250 movies, and I lost all of my runtimes, and now I also have a bunch of movies in the top 250 that should not be there. All of the movies that should not be in the top 250 list that are showing up when filtered, have the tags formatted incorrectly as follows:
<top250>
</top250>
Where movies that are not supposed to be in the top 250 and are correctly not showing up when filtered are as follows:
<top250>0</top250>
All of my runtimes are as follows:
<runtime>
</runtime>
*Update* I just selected all of the movies and right clicked on the movies, selected rescrape specific -> runtime -> from IMDB and it fixed them all. So it looks like it is just the batch rescraper wizard that is causing the problem.