Google Search Console reports some URLs as "Duplicate without user-selected canonical" and then "guess" the canonical URL or do not index at all.

Examples:
https://musicbrainz.org/artist/c2b10d7d-ad76-43ed-847b-f2059a49b3bc?va=1
https://musicbrainz.org/series/f334683a-7a48-4d41-82aa-e62058a258b5/show?page=1
https://musicbrainz.org/label/49f9d59f-94b4-4005-8346-78bfd6c55c3d/show
https://musicbrainz.org/release/e91ba44b-7f28-4eda-aa3d-44a65e4760fb/edit-relationships

And many more.

It would be a good thing to implement solutions suggested in https://developers.google.com/search/docs/crawling-indexing/consolidate-duplicate-urls

See also this example:

In this case Google Search guesses the canonical URL totally wrong:
For https://musicbrainz.org/artist/a94587df-19a5-49bc-b895-1cb95af93002/subscribers it selects https://musicbrainz.org/artist/create as the canonical URL...