MySQL: duplicates with nested select and DISTINCT

Question

Following this question: Remove duplicates on MySQL JOIN query on JSON_ARRAYAGG with INNER JOIN

I have an app with users; the users can create bookmarks, and each bookmark can have multiple tags, as well as be private.

So, if I'm not mistaken in the notation: user =* bookmark *=* tag

I want to retrieve the users with the tags they used in their bookmarks. But, there is a detail: we are going to have the @SESSION_ID available in the query: if the bookmark is private and the user that created it is not the one in @SESSION_ID, don't return it; do it otherwise:

SELECT
  `user`.`id`,
  (
    SELECT
      JSON_ARRAYAGG(
        JSON_OBJECT(
          'id', subQuery.id,
          'name', subQuery.name
        )
      )
      FROM (
        SELECT DISTINCT
        tag.id,
        tag.name,
        bookmark.user_id,
        bookmark.isPrivate
        FROM tag
        INNER JOIN bookmark_tag ON bookmark_tag.tag_id = tag.id
        INNER JOIN bookmark ON bookmark.id = bookmark_tag.bookmark_id
        INNER JOIN `user` ON user.id = bookmark.user_id
      ) subQuery
      WHERE user.id = subQuery.user_id
      AND
        (
         subQuery.isPrivate IS NOT TRUE
         OR
         subQuery.user_id = @SESSION_ID
        )
  ) AS tags
    FROM `user`
  GROUP BY `user`.`id`
;

As you may see, if the bookmark is not private or @SESSION_ID doesn't match the user in bookmark.user_id, there will be no duplicates; but if the bookmark is private and @SESSION_ID matches, some duplicates will be returned.

Here is a fiddle: https://dbfiddle.uk/?rdbms=mysql_8.0&fiddle=7ae76ba61c5870c3a9f31d9564538fa1

Any idea will be welcome!