@kamikazemoonman:
JDownloader only checks for filenames if the site/api can provide *safe* filename information. Not every site does and thus JDownloader has to process the download and wait for final download to begin in order to get hold on a *safe* filename.
See answer of pspzockerscene to allow *unsafe* filenames for local checks.
As far as I remember, there is also a script that will check local files and mark files as finished,search here
https://board.jdownloader.org/showthread.php?t=70525