> packaging _

The subsystem collection scans for subclasses once, when it is initialized, and sees only classes already in memory. In a packaged build, a Blueprint class that has not been loaded by then is missed entirely: its CDO is never asked whether to create an instance. The Blueprint logic never runs, and the missing class produces no error or log entry. In the editor, the Content Browser can keep the class loaded and hide the problem.

By default, staging copies files from Content/Movies outside the pak as NonUFS, which is why .mp4 files sit loose in the build directory. Turning on bSkipMovies and listing the file under UFSMovies pulls it inside, and playback through UMediaPlayer with FileMediaSource keeps working: WmfMedia on Windows reads through IFileManager, which can access files inside the pak.