Show hidden tracks and albums in overview

I use a nuc for the core (rock) and bluesound vault for the library. On the core I use an internal drive for backup of the library ( also useful when the vault is switched off)

Not a big thing but…

In the overview screen I do not see double cd covers (unless I switch “show hidden tracks and albums on”) but the counting of the albums and the tracks etc stay doubled in both views.

Er, isn’t Roon working as designed? If I understand you correctly, your Core is accessing both your Vault, and the internal drive on the NUC as watched folders (you say that you are using the internal drive as “backup”, but then you say that it’s also useful for when the vault is switched off, which leads me to think that it’s also being used as the default Music folder in Roon).

So therefore your library has everything doubled, and Roon is reporting this correctly.

I just wonder about the difference between the counts in the top row of overview (which counts always the doubles) and the album counts in the album view which shows the album only double in the “show hidden tracks and albums”.
So Roon has the information about doubles but uses it only for the album view, including the album number on top on that page (see 645 vs. 1287) but not for the countings of the albums (and the tracks) in the overview page

In the overview you always see 1287:

not a big issue, I just wonder why.
Why not show in the overview the counts with the doubles between brackets like:
645(1287) ----- 9734(19468) ------- 414
Albums ----------- Tracks ------------ Artists