I just went to play a Christopher Hogwood album by going to the Artist, pressing Discography then limiting to my library.
According to Roon I have 6 albums , in fact I have 42 !!
If I navigate to a missing album via the album view I can find them and everything looks fine.
I am not sure if this affects other artists ???
I have restarted the core, now rebooted the core. The network was restarted just before the issue was spotted. Other artists look fine so far
Confused …
bbrip
2
No need. Help is at hand 
Its a known bug. See here: