[Question] Windows 8.1 'File History'; '$OF' Folder

I decided to give W8.1's 'File History' a try because I'm tired of Acronis TIH orphaning incremental backups (I doubt it was fixed in 2014 edition).

The problem is I have a folder '$OF' that has many files in it with the naming convention of: 4593 (2013_11_09 21_33_36 UTC).mp3
-Of course each file is named slightly different and the file types change depending on the original file. But the naming method remains the same

Now this wouldn't be a problem, but I have some 330GB of music...of which only ~280GB appear in the 'G' folder, which contains the 'Music' folder. My music in on my 'G' Drive; hence the parent folder being named after the Drive Letter by Window's 'File History'.

I've not been able to find anything that actually explains why some files are renamed to the above convention, while others are properly backed up.

In fact, because I've tagged my MP3s, I've noticed that some of the MP3s in the '$OF' are still backed up to the 'G\Music' folder under the appropriate Artist and Album folders.

I thought this ['$OF'] might be some kind of temp storage used during the initial backup. This is not the case. 'File History' reports it's done, but the stuff in the '$OF' folder remains.