I just encountered a major annoyance (for me) while moving around some paths of movie directories.
Host name of the file server is ‘artemis’
Initially I set up my paths manually, i.e. smb://artemis/Movies/ (via “Add network share…” – in german “Netzwerkfreigabe hinzufügen…”)
By mistake I removed the source, but added it again right away, when i realized it.
This time (unfortunately) I chose “Windows Network (SMB)” and navigated to the server and share.
The added path was smb://ARTEMIS/Movies/ (with the host name in all CAPS).
Everything seemed to be fine, but then I noticed that I had all movies twice in the list – the second one always marked “unwatched”. Aaarrrgh!!!
Cleaning up the library didn’t help either, since both file names are still valid! 
I consider this a bug in KODI… The host names of smb:// shares should not be case-sensitive!