Windows 7: Backup Skipping Files with No Error

So I guess this is pretty straight forward. I have a folder with 5 files in it. When I set the backup to backup that folder it just willy-nilly skips 2 files of its own accord. No error in event logs. The program that uses these files is closed when the backup runs. Any ideas? I attached a screen shot of the actual folder and what it looks like when it is restored just in case it might give a clue.