I was accessing files over a Samba share (Debian 8 (Jessie) as server), when some filenames were not the way they were when watching them on the server (using "ls"), but random uppercase letters in legacy "MS-DOS 8.3 notation".
For example:
"01 - author : title.txt" becomes "0HPENP~T.TXT"
Very confusing.
[SOLUTION]
The reason was that the filenames contained characters that unixoid filesystems (ext, zfs, etc) can handle, but Windows can't.
Therefore, Samba "cleaned" these filenames - but not in a very sensible way

That's a reason why I am very very picky about clean filenames!

Here's something that you can use to clean your filenames before trouble happens:
http://detox.sourceforge.net/
Links: