Artist View Not Displaying All Albums Under The "With" Section

I have been using Roon now for about 2 weeks, and one thing that I have noticed that really bugs me is the artist view not displaying all albums under the “With” section. Although I have all the albums in my library.
For example when I select Artist “Robert Plant”.
The “Main Albums” Seems to be missing 1 album.
The “With” Led Zeppelin displays 10 albums, and is missing 7 albums.
This is for official albums, I have not included bootlegs in the totals above.
If I include all then “With” displays 12 out of a total of 144.

Is this purely down to the metadata that Roon pulls off the servers, or is there something I can do locally to fix it.
Under settings>Library>Import Settings I have everything set to Prefer Roon.