iTunes add to library won't pull PDF and doesn't get all songs

So i'm running itunes 11 on osx 10.8.4 (all newest since this date). When I add folder to library, i started with my folder with many epub books and pdf books. it imported all the epub but no pdf. If i manually click on each pdf to import it will impoirt them. why won't it grab all the compatable files in the folder i'm importing.

ALSO, i imported a large 50gb music folder. Appears it imported everything then I notice 1 or 2 albums missing. I re-import the folder and it will import SOME of the albums it missed. Then I import the same freaking folder and it will import a few more files it missed.

Why is iTunes not getting all the files in one import then has no notification it was unable to import any files?

I ended up importing a folder with "copy to library folder when adding to iTunes" and the "keep folders organized" checked. i thought it got all of them so I deleted the other folder. low and behold it imported about 95% of the folder. this is VERY frustrating and itunes is doing the same thing to me on my windows 8 PC running itunes 11.....

Anyone know if this is a bug?