The movie total at the top of the library goes down when you add movies to ‘Hide movies in this Collection’, collections.
Currently it gives a total number of items in the library, even if one item may be a collection hiding a hundred movies. So, with enough movies, and collections, the total could be drastically wrong.
I’d love a setting to change from ‘total items in library’ to ‘total number of movies in library and collections’.
The only way i can currently get an accurate number is to delete all my libraries. That seems a bit overkill just to get an accurate total.
There’s already an existing feature suggestion asking for such an option (incl. an explanation that the number displayed at the top of a library is the number of visible items, not movies… as you determined yourself).
I suggest you comment/vote in that thread in order to avoid distracting/dispersing votes.
There is a much less destructive and quicker way:
Simply change the ordering of the library view from “by title” to any of the other options, e g. “by year”.