Thumbnail Cache With Media Library Using Network Share?

WD Legacy Products WD TV Live Streaming
1

I have an external hard drive that caches all of the thumbnails.  I added network shares to my media library last night, and noticed that it doesn’t cache the thumbnails.  Just wondering if this is normal or what?  Thanks for any help.  

2

As far as I know, that is only supported on hard drives connected directly to the media player.