Sounds like you are using the Media Library and set it to “Auto” Get Content Info.
Select “Manual” … delete all the movie and series XML files the “Auto” created.
Then, clear the Media Library … and/or shutdown the WDTV (unplug from the power for a minute or two)
switch back on … names should be back to normal.
Lastly, if you don’t want the Media Library On … then turn it Off.