@connor, I found lots of dupes after all. They are hard to spot because they are all over the place:
The Camerón de la Isla album here is listed in the correct spot, at the letter “I”. Note the others around there, the letters “I” and then “J”.
I have two versions in my library, and there are several more Qobuz and Tidal versions:
When I scrolled past that, I saw that the mp3 and the Qobuz in-library version were shown separately (although I have version grouping enabled), and so I selected them both and did “Group alternate versions”.
Then I continued scrolling and got to the letter “M”, when suddenly it restarts with artists with “E” (Missy Elliott has the sort order “Elliott, Missy”):
This continues with “E” through “I” (all of these albums were already shown further up in their correct spots), where we find Camerón de la Isla again, this time still shown as ungrouped:
Continuing with the letters “I” through “L” until we reach “M” again, all seen before:
and then more "M"s, which were previously not yet seen, and then further to N, etc.
I wanted to range-select all the duplicated ones from the wrong Missy Elliott until the “Ms” restart again further down, but of course this doesn’t work because as usual all the originals further up get selected, too, and everything in between.
EDIT: This is incredibly hard to screenshot and explain because every time I scroll through, it seems to look different. I notice that the letter at the scroll handle also seems to get confused:
Here I scrolled, using the handle, to what I think is the “real” letter M area:
Then I scroll farther and then lower letters repeat, e.g, suddenly we are at F again"
Then I scroll farther and there are more “M”:
EDIT 2:
I have restarted the Roon Server and the dupes are gone
