Why does the query select everything from the database and not 20 records?

Question

SQL

SELECT `chapter`.`id`, `chapter`.`slug` as chapter_slug, `manga`.`slug` as manga_slug, `manga_id` 
FROM `chapter` JOIN `manga` ON `chapter`.`manga_id` = `manga`.`id` 
WHERE `chapter`.`id` IN 
(SELECT * FROM (SELECT `chapter_id` 
 FROM `page` 
 WHERE `compress` = 0 
 GROUP BY `chapter_id` 
 ORDER BY CAST(`page`.`filesize` AS INTEGER) DESC LIMIT 20) t1)

Selects all entries. Why?

SELECT * FROM (SELECT `chapter_id` 
 FROM `page` 
 WHERE `compress` = 0 
 GROUP BY `chapter_id` 
 ORDER BY CAST(`page`.`filesize` AS INTEGER) DESC LIMIT 20) t1

Selects 20 pieces.