Bizarre library naming

Hi

Just something a bit strange. Been running serviio for quite a while on my QNAP Ts419, and everything perfect. Accessed the library a couple of weeks ago, and find that about 20% of my movies have been renamed 'prem pujari' according to serviio (the files still play fine, and still have the original names on the NAS BTW).
Wasn't sure if the issue was the version of serviio I was using, so I updated to 1.5. Re-create the library, everything fine. Two weeks later, I suddenly have about 30 movies named 'prem pujari' , again, plus files renamed at random.

Any thoughts?

[DenyAll]

Look for strange files in the folder containing your movies - .nfo files for example. They may be hidden.
What happens if you move the movie to another shared folder?