[DaveBlake]

Existence of art is not important, but even without debug on I can see that the player is having difficulties...

PHP Code:

ERROR: Open - Unhandled exception
ERROR: Open - Error opening nfs://192.168.20.19/volume1/media/Music/1927/Ish!/04 You'll Never Know.mp3
ERROR: Init: Error opening file musicdb://artists/2/1/4.mp3?albumartistsonly=true&albumid=1&artistid=2
ERROR: CAudioDecoder: Unable to Init Codec while loading file nfs://192.168.20.19/volume1/media/Music/1927/Ish!/04 You'll Never Know.mp3
WARNING: PAPlayer::QueueNextFileEx - Failed to create the decoder 


Have to investigate more, and interested to know if OP has the same issue or not.

This looks more like  a network issue, Kodi unable to access te NFS